It always starts with ownership and Harris is not a good one though I think Michael Rubin leaving was probably a plus. And The Process wasn't going to work out either way it seems, nor would Hinkie have been able to be run the post-Process team. I mean, we ultimately hired his mentor and he's not that great either (here or in Houston. Good, but not great).
But the key failure points - Simmons, Fultz (bad trade but justifiable pick), picking Harris (and Ben) over Butler all probably still would have happened without the incompetence of the Colangelos. The no-GM year (when they traded Mikal Bridges) and Brand tenure were probably worse (but never would have happened if not for the original sin of Colangelo, and no good GM wanting to work for Harris until Morey wanted out of Houston).
Nor is the reality of Joel anything that could be changed (and we don't even get to pick him if he's fully healthy at the time).
But hey, they did draft Maxey.