I don't think Harris is tradeable for equal value. You'd end up taking a couple of pieces of trash to make the money work, and might not even get as good a player. But certainly they are not stuck with this group next year.
It's certainly not untrue that Brand has built a mega-talented roster, but the pieces don't fit each other, or, perhaps, the coach, and that's on him. The plan was also to have such a dominant starting five (especially on defense) that the lack of a shooter and the thin bench wouldn't matter and while the bench has actually been better than expected, that hasn't been the case.
I don't really blame Brand himself for anything, he had to clean up the Colangelo/no GM mess. But better GMs also weren't going to get the job (either because they didn't want it or Harris didn't want anyone with real power. Even if he has made Brand the coach's boss finally).