The community destroyed the game's balance.
That's all there is to it. The community has brought cataclysmic imbalance to the game, not Riot. All of you out there are to blame for the state the game is in right now.
Why? Because the overwhelming majority of you out there are not just all ADC and assassin mains, you are ADC and assassin EXCLUSIVES. All you do is play Yasuo day in and day out, use the exact same build against every opponent, the exact same tactics, the exact same everything. You ignore everything that isn't teamfights and pentakills. Once the lanes open up, you refuse to push or defend ANY lanes; you place higher priority on jungle camps than anything else, and you don't even THINK about defending until two inhibitors are down and you are forced to defend, which the majority of you are simply incapable of doing even in the best of circumstances, especially with single-target champions.
You don't go for dragon or baron; you BARELY even go for minions post level 8. You don't build armor penetration for tanks or Grevious Wounds for super healers. You don't build Maw of Malmortius for mages so you can continue to deal damage AND not die. You treat your trinket as mere decoration and never use it, relying instead on the support to ward everything for you. You don't take advantage of the enemy's absence to claim an important objective, squandering that late game 60 second death instead on farming as much of the jungle as possible, even though you maxed out your build and you have a 3000 gold surplus besides.
And yet every day I come on to this forum and see thread after thread after thread complaining about how overpowered Soraka is or how tanks rule everything or how mages are instant nukes. Yet in every game I'm in, I see people say the exact opposite at the start, that the only good champions are Zed and Yasuo and everyone else is below trash tier. Then when they get their asses handed to them, they whip around and say that everyone is too overpowered.
No, the problem lies with all of you, who outright refuse or are literally incapable of even acknowledging 99.99999999999% of the game's mechanics in favor of the one that you saw someone else get a pentakill with, and because THEY got it, you think you can, too. You say you really really REALLY want to win, but you don't do even a millionth of the things required to actually get there; you want it handed to you on a Challenger platter. You like to flap your mastery dicks at the enemy AND your allies all day long, but the very instant you encounter something even slightly hard, you buckle, you snap like a dry twig, and you retire to the fountain and wallow in pathetic depression when your power fantasy comes crashing down on your heads like the Hindenburg.
There's a whole universe of balance out there that you completely missed, but at this rate, you'll never even know it exists.