The issue is snowball. Clean and simple.

Matches are one-sided because of one costly mistake made by one player. The game devolves so hilariously quickly after each buff transfer, each first blood, each first blood TURRET, each meaningful drag, each herald, each baron, each missed smite baron. The game is all but perfectly engineered to end itself as quick as possible.

It's as if Riot doesn't want anyone to play their own game anymore.