Personally, I have a few reasons why I quit on a consistent basis.
- Balance Problems
There is simply no way to keep League of Legends in a balanced state for all of the game's audience. Just because Zed is balanced in professional play where everyone has the reflexes of a god and the predictive skills of see previous, doesn't mean that in Bronze he's not going to just shit-stomp everyone. You know, bronze. Where everyone has the map awareness of a blind cartographer, and the reflexes of a dead sloth. And, of course, as the mid laner, it's your fault because you didn't follow them, despite the fact that you pinged bot lane 17 times before he showed up.
And that's not to mention that it's been eons since AP mages have gotten any good new items, where it seems like Riot is constantly adding new tank and AD items. And, I mean... would it kill them to give us at least make Seeker's Armguard not a horrible waste of gold against assassins? Please?
Not to mention, seasons go from Season 7 to where games last far too long and are super frustrating, to season 8 where the end in 12 minutes and are also somehow just as frustrating.
I'm not saying that Riot needs to chuck out everything about eSports, but roughly 90% of their playerbase is contained within unranked accounts, and people in bronze. So, it's understandable that some people in bronze might be really frustrated and they might leave. This is why we see such a disconnect on the forums - from what I can tell, the forums have a much more even ratio of bronze to higher level players, so threads asking about balance or ranting about changes in the balance of the game get smacked down very quickly by higher level players, and there's a lot of fighting about it.
- Alternative Options
Most people started league of legends like you did, with real life friends. Now, the gaming landscape has changed. It's just not as easy to assemble the 5 teammates you want, especially if the team started years ago, when the members had nothing better to do. But, life goes on. In the span of 3 years, your friend group may have people graduating from college, or joining the work force. They might be starting med school or law school or something, for all I know. These are things that happen that end up breaking up full teams in league of legends.
And, when teams dissolve, there isn't as much of an incentive to keep playing, and, sometimes, people float to other games that their friends who moved on play, or that they can play with a different group of friends.
Not to mention that people are really discounting how popular Fortnite is - it's single-handedly killing a long list of games that are either in beta, or are relatively new.
- The eSports Focus
By and large, I think this is one of the biggest, if not the biggest issues, a lot of people have. It kind of overlaps with the balance problems that lower level players are going to experience, but combined with them pushing eSports, and having players tell them they are just bad at the game because they aren't as good as Faker or BoxBox or some other popular player, they feel like the game isn't a place for them. They start to feel like this game isn't meant for people of their skill level, and that they aren't welcome.
And, really, it's very hard to play at a high level, because of the sheer amount of information that you need to memorize to be a good player, and all the matchups you have to study.... and, even if you're really good at one role, if you don't at least have a good idea of what the majority of champions do in the game, you can get utterly destroyed by some oddball pick like Sion support, or Lulu top. I've seen it happen - I mean, most people know the Lulu top was and still (kind of) is a thing, but they're not usually prepared for it, and will often lose to it because they don't have the game knowledge to know how to handle the situation. And that's just a small facet of what you need to know.
This game is incredibly complex, and there are several things that you might not even know to do, because it just never crossed your mind, and no one ever told you to do it.
In the end, I personally feel like the ranked queue is kind of a playground until you hit like... plat or diamond. Because, really, from bronze to even gold, you can just see wacky things happen, that you either aren't prepared for, or just don't understand how to deal with.
And eSports have gotten boring. No one makes any plays anymore. You don't have like... crazy aggressive things happening in mid these days. It's because they know that farming is key, and they could risk it all and get a huge lead... but inching ahead by slowly and surely denying CS and grinding down your opponent slowly but surely is the safest and most often taken option. I just don't watch eSports, but Riot is constantly pushing it.
- The stupid paywall
Seriously, Riot has gotten more and more out of line with their payment system. Now that they've combined runes and masteries, you need to buy rune pages to play the game, unlike mastery pages were you could have a rather large number for free. At the very least, back then runes weren't that influential. But now, you can't just play with no runes.
Oh sure, you can buy them with BE... or, because they're ludicrously expensive and it will take you literal months to accumulate 6,300 BE unless you play constantly for hours per day, you better be happy with changing your runes on the fly. And since you can do that, it makes it pointless to have us pay for rune pages in the first place. It's not like you're locked into the two pages you're allotted, with a few boilerplate standard ones and that's it. You can change the runes at champion select - rune pages are a scam that just make things slightly more convenient.
Not to mention that they keep saying it's easier to get new champions with the new level-up rewards, but I think it made things markedly worse.
Let's say, for argument's sake, you want to unlock Pyke on launch when he comes out in a few weeks or whatever. You're going to need 7200 Blue Essence. Let's say you have 1200 Blue essence. How long will it take for you to grind up to enough blue essence? Well, the only way you can obtain blue essence by itself is your daily win bonus of FIFTY BLUE ESSENCE. So, if we were to assume that there are no other missions that grant blue essence, and that you don't level up or have any champion shards to disenchant, that means you'd be grinding for a grand total of 6000 blue essence, and that means it will take you 120 days, or 4 months.
But, let's be realistic. Let's say you level up once every two days, and you get the minimum amount of loot every time, 810 Blue essence. But, since no one is a machine and no one is going to crush all of their champion shards indescriminantly, let's say you level up twice per week instead of once every two days to account for chests that contain shards for champions that you want. So, that leaves us with 350 BE off first win of the day, and round it out to about 1600 blue essence just to make the math easy. That means, you'd be grinding for over a month to get enough essence to buy this new champion, and you'll have spent ALL of your essence. That means you have nothing to fall back on if you wanted to fully craft a new champion out of shards you get later.
And, finally, the Blue Essence cost is too damn high on champion mastery. I spend months saving up the 8000 Blue Essence that I currently have - I don't want to blow over half of it on upgrading my mastery emote to a shinier new one, so I'm going to stubbornly wait for a champion shard of the champion whose mastery I want to increase. I had to wait 6 months for a final Veigar shard to drop - not kidding. I had 3 mastery tokens for Veigar for 6 months before I saw the shard I needed.
Now combine the fact that you have a 1/130 (possibly less) chance of you finding the champion that you want to try out next, and that champions are absurdly expensive to not only get mastery for, and absurdly expensive to buy without a champion shard, and you have a crafting system that I absolutely hate. Should I crush my Urgot shards? Well, no, because I just started playing him, and I like him enough that I want to get his mastery completely decked out for when I wipe the floor with some top lane scrubs, so I'm not going to get that Blue Essence, I'm going to sit on that champion shard for a few months while I grind out some Urgot mastery tokens. Should I disenchant those Nidalee shards? Well, I have no desire to play her now... but what about later?
This indecision is just a killer of my spending power, so I'm sitting on like... 60 shards, and I'm afraid to disenchant them in case they'd be useful later.
And, hextech crafting is BS now that they've added emotes - just saying. I barely get skin shards anymore out of chests. It feels so super cheap to get a summoner icon, and 2 emotes in a row.
- Champion Neglect
There are some champions that Riot hasn't tried to make viable for years who have their die-hard fans. And when you're a die-hard Teemo player, no Teemo builds are viable, that hurts. And, I've felt this. I can't play Veigar anymore. Everyone's playing Katarina, or Ekko, or Zed, and they're just too agile. Your stun is too slow to catch them, 99.9% of the time, and your mana issues early make for an easy lane for assassins. Not to mention that Electrocute does WAY too much damage early on, something that Veigar can't handle. He hasn't been changed to reflect the current state of the game, and I can't deal with this new mid lane setup.
Not to mention that, when they change runes and not the champions affected, they can end up super weak and unplayable.
Hell, I feel really sorry for Amumu players. He hasn't been super viable over another pick for an awful long time, and is in desperate need of a rework. Like, seriously, I wonder how people even still play this champion in the state he's in.
But, hey, that's just my 2 cents' worth.