I'm reluctant to write him off on the basis of his entire body of work. However sports fans have short memories, and this one trade, viewed negatively, will probably overshadow everything he has done for the franchise so far. Nobody cares about past championships, they care about the here and now.
My thoughts are that I'm reluctant to pass overall judgement on him without knowing the full story. He hasn't even had a chance to explain himself. I feel there's got to be more to this than what's being reported. On its own merits it would appear to be a lopsided trade, trading an All-NBA, All-Star, two way wing who was 2024 Finals MVP and was 6th in MVP voting this season for a guy who by popular consensus had one of the worst contracts in the NBA. And Philly only had to give up two firsts and two seconds to get rid of his contract.
The only way this would make sense is if it is one part of a bigger set of moves that lead to us being a net better team overall. Then you might be able to accept why Stevens appeared to give up a lot for not very much in return. Even taking to account Jaylen's advanced metrics not being great (I posted Jaylen's on/off over his career vs JT and PG13's in
this thread he still was an important part of winning a championship, he won Finals MVP and he finished 6th in MVP voting due to his overall production and impact.
Speculating on what we don't know, either of these things could be true, which would be a way of defending (clutching at straws) this decision:
a) there has been a relationship breakdown, either between Jaylen and the organization, or Jaylen and Tatum, that they deemed to be beyond repair, and that could affect the harmony of the locker room. Why this happened after 10 years, who knows. But they do happen. You'd have to think that Jaylen probably knew this was coming, he wouldn't have been blindsided by it.
b) it's about the money. Jaylen is eligible for an extension this year, it would have been at minimum a 2 year $140m extension ($70m AAV) starting in 2029-30, or up to a five year extension at $325m ($65m AAV) if he had reached free agency. It's possible that Brad was thinking ahead and didn't think Jaylen was worth paying that extension for so he moved him now, for a guy who, while being overpaid for his production, will come off the books end of next season.
On its own merits, looking at it in a vacuum, it looks like he got screwed - he gave up an All-NBA asset for a washed up has been. So I'm looking forward to his justification for it, I feel he needs ot do that to settle the fanbase down and help us understand his reasoning.