I don't think LoL has become more of a team game from last season

When LoL used to let people carry 2v8 it was considered a less 'team' based game and more about carrying

but right now it's not any better, when 1 person feeds the game is over.

It may sound like that means every person should do well to win the game now, unlike before when two to four people doing well enough can still carry, but in reality it means the game's state was defined by that one person feeding rather than a team-wide fail.

The only thing that changed was the emphasis: One person could win the game by doing well enough, so the game was about being most fed. Now one person can lose the game by feeding hard enough, so the game is about being least behind.