Why not just do 2-2-2 in role queue?

I haven’t played the game in a few weeks so I might be a little out of it, but why doesn’t the 6v6 role queue just have 2 tanks, 2 dps and 2 supports instead of 1 tank, 3 dps (1 of whom can switch to tank, as per my understanding) and 2 supports?

Like, we agree that people who like 6v6 like so because of the extra tank? I’m not really sure what percentage of players prefer 3 dps or 3 supports over 2 tanks. Especially since, atleast in my experience, beating an enemy team with two tanks whilst only having 1 tank on your own team is a miserable miserable experience (unless there’s a huge skill gap).