Coaches are not the primary reason that basketball teams do well or not, win titles or not; they affect winning, but not as much as the players do, including the health of the players. But I feel that if you coach a team to a title, that does mean something. Not the end all, maybe more of a floor.
I generally give Mazzulla a pass on the meltdown in 2022-23. I think that was about a lot more than good or bad coaching. But Mazzulla has to own the good of 2023-24 and the bad of 2024-25. I still believe that winning or not is more about the players than the coach, but the coach does not get a pass when a team underperforms.
2025-26 is now a lost season that will have no bearing on how good of a coach Mazzulla is. But 2026-27 and beyond, the team needs to perform. I am fine with giving him that much leash based on the title. The extension doesn't really mean much. He will still be fired if the team doesn't perform. No luxury tax or other penalties associated with that salary.