You underestimate how often people would quit or AFK. Or they would just be terrible, no mic, lots of other things to come on here and complain about. You WOULD complain about it at some point. Matchmaking is not the solution for this type of content. But I don't care either way. I find people to raid with, 3 times a week. Doesn't bother me that you don't. It takes 2 minutes, faster than matchmaking would be.