Continuing the discussion about Brett:
In the NBA coaches affect:
Team Culture - Brett seems to be one of the best at this. Players like him, want to play for him, and generally respect each other. Free agents seem to want to sign here. He's respected around the league.
Offensive Scheme - I like the DHO motion scheme they run, but I don't think Brett has adapted it well to his personnel
Dead ball plays - again, Brett, or his assistants, have historically been very good at this, but this year has been less impactful in this regard
Defensive rotations - their main focus on defense is to deny corner 3s and funnel players into Embiid - they have been successful at this if you look at the stats. Their P&R defense needs to be adjusted.
Player development - this would be my main beef with Brett. He seems to not work consistently well with young players, and developing stars (Simmons, Embiid) don't seem to be improving the way that is expected.
Player usage - I think he plays guys too many minutes, but that's a problem league wide. And guys get in his doghouse (Ennis, Burke) for no apparent reason and disappear
Team Effort, to a limited extent - historically the team plays hard for him, but this year they seem to be mailing it in way too often on the road
I think they need a shake-up, and that can be a new voice as head coach, but it could also be a player move. I think I'd probably let the season and playoffs play out, then move on if things don't improve.