I think I understand why Riot removed Solo Queue

They figured out that their game is hitting a point where it's so bad that people don't want to play alone. If you don't play in a group the game is in an even worse state. Basically the game has hit a point where the game is toxic period and grouping helps to cover that up. You supposedly get to talk with like minded people instead of randoms and have more fun which helps mask how bad a state this game is in.

I have a lot of friends who used to play League. The key word is used to. Even with a full party they do not enjoy this game anymore (I have had 5 close friends quit in a year) and they were fine with it when solo queue existed (most quit after S5 started).

League is hitting the point where the fun doesn't exist to solo anymore. It's extremely competitive and putting people solo against groups in a competitive environment just breeds more toxicity. It leads to bullying as well as peer pressure. Something that normally wouldn't really effect people in a 5v5 environment because you have 4 other people you know so it's not 3+ people hounding on a person all game.

To top all this off League is in a burst meta (thanks to thunderlord's and grasp) which favors 2 things. People who are tanky damage and people who already put out a lot of DPS aka bruisers and ADCs. Tanks having damage has always been toxic and now their items are even favoring it. Just look at and alone. 2 Tank items that do damage for building tank. And then there's which quite honestly shouldn't be an automatic passive and shouldn't increase tank damage because we know how this went in the past: Atma's old issues anyone? Same reason Sterak's is abused. It just works better on ADC's. And in order to fix that they have to make it not be a damage item.