If PvE endgame can somehow be made to scale to average fireteam level and adapt as people change their level up and down as they adjust their setup, then great. As it is I find that the pretty average players that I mainly play with still find endgame hard. The really good players that I play with on occasion can cream through endgame and have a laugh doing it for fun. but throw 1 braindead onto that same team and the difficulty goes right up to max. Unfortunately, I play with friends, and sometimes you can't just kick the dead weight, because they're your IRL buddy, or your work colleague, or your friend's kid. That keeps endgame plenty hard for most players.