I was 10/3 with Raka this week (until I got into promos and had 3 AFKs in a row) now I'm like 11/5, so sad. You can carry as pretty much any champion in B5 (well I'm in B1 but still).
Yes and no, some people find competitive play to be fun. You didn't get to level 30 without playing the game for fun, but I'm sure you also played the game to win games. You didn't just lose 10 games in a row and be like 'lol that's okay that was super fun' you were playing A) for fun and B) for win. If you're playing a game for fun then a game can fit both of those circumstances, if you're not playing for fun then it can't.
as for the next paragraph it has a lot to do with everything. The reason you didn't get strive for Silver, no matter what you claim, is because you weren't intrinsically motivated to get there. Anybody who aims to climb a ladder like that needs to be the kind of person who is motivated by themselves and not by outer influences to actually do well. A reward only motivates somebody to try harder if it is considered to be a simple task like offering a child $5 to do the dishes will get them to do the dishes. A reward will not fully motivate a person to try harder for a task that is considered a complex task as climbing the ranks of LoL is. Going from Bronze to Silver is a huge time commitment that requires knowledge of in multiple areas. As such it doesn't matter what League of Legends was offering a person to get go from B5-S5 because you aren't going to be any more likely to get there. Aka the reason you didn't get to Silver, or even try to get to Silver, was because you weren't motivated yourself to get to Silver, you were looking for some sort of reward from Riot to get to Silver. That only works in very high Elo where they are competing for money and money helps people satisfy their basic needs for living.
We should get something that feels worthwhile for playing, and the people that succeed should get increasingly more worthwhile rewards....This is something I actively felt, in Bronze V. There was no way I was going to get all the way to silver for the next reward, so why bother?
That's what that paragraph was responding to, when you mentioned getting to Silver you said you weren't going to make it to the next reward and therefore you had no reason to try. I was also responding to this:
if I'm not getting a reward, what's the point of working to get better?
because like I've said in the longterm (aka a year long season) a reward won't motivate people who are motivated for the reward. Only people who want to get better and are playing for reasons inside themselves are going to get better. Aka the reward Riot gives is a nice bonus but it shouldn't be a big deal.