I think the Bucks' problems have more to do with the FO and GM than Rivers. They added a very good but aging player in Lillard. Giannis is in his prime, but he's surrounded by older players. To compound it, they gave away draft picks to get non-contributors like Crowder. Crowder is gone as well as the draft capital they gave up to get him.Last night the Bucks reverted back to the sub .500 team they really are. The tinkering and playing with the lineup, and alienating players has followed the history that Rivers had as a HC in every stop. This team will be dismantled, and we won't see a decent outcome for several years I'd guess. It seems like Rivers has decided it's the guys on the bench that he mismanages in giving them playing time, that are the problem. It's why guys who played roles on all his past teams opted out in free agency the first chance they got.
Fifty years between championships. Horst just couldn't help but destroy the team by tinkering.
I hate to say this, but the best way forward may be to trade Giannis and get some draft capital back. Same for Lillard. Lopez and Middleton aren't worth much as far as a trade. Bottom line- they need to rebuild with younger guys. It's gonna take some time.