I've done every AV and monster in the game and all of them were doable with a team of equal level intelligent players. Lazy people will seek level 50 help, smart people will just pound them.
One thing that bothers me about this statement is certain arcs may be ruined by this. Springing to mind are some of the 40+ arcs and more noticable is the Envoy of Shadows arc where you have to fight the AV several times and it's a very tough AV I doubt anyone at that level could solo.