4/5 games are pure garbage, impossible to play due to the trash riot burdens good players with. I see only 4 possibilities :
1)games are rigged
2)match making is cancer
3)riot is inefficient to detect, or careless with, boosting and win trading
Clearly riot failed to mention soloQ is unplayable for ACTUAL solo players and you need AT LEAST a good premade just to offset the uncarryable garbage they force you to carry and have a SMALL chance to get a decent game.