Where are the bans on the players that make games unwinnable?

Riot has been banning people like crazy lately, and handing out mutes like candy. But the game is still going to shit, most bot lanes i see refuse to group, acknowledge any teammate, push for any objective other than bot lane tower, completely ignoring dragon, ignoring the 3 enemy team members walking up river past 3 wards to gank that are being pinged, pushing to tower nonstop the entire game, never grouping, never saying anything in chat. These players ruin the game for everyone, and in being silver i feel like 90% of games are decided by which team has this type of bot lane. Why are players like this never banned? Why does the new reward system reward players for never speaking because if they say just about anything they will get muted and permanently no longer receive rewards? This game is no longer even remotely fun, riot needs to do some serious cleaning up...