IMO people are really bad at remembering how much DPS is actually needed to clear content and very easily groups failing to mechanics would just kick a new player even if said player was doing really good for where he is in the game and how hard it would be to judge him against a very geared DPS doing a bad job.

I wouldn't mind having a personal DPS, you can compare yourself with previous performances and you can just as easily talk to others to see how everyone is doing.

IMO FF14, seems to have the best experience for solo players queueing, most of the time people are happy to have someone new to the group to get bonus and to actually be receptive of bad plays and help others when things fail instead of having people bragging about how they are "carrying" the group or how someone needs to get kicked.

If you really think that would never happen then you didn't play enough other MMOs to see how toxic it gets.