I don't think this is true at all. First, a team that wins also loses players, which is what makes it so hard to repeat. Second, there are 29 teams that don't. The vast majority don't blow it up. Third, I would argue that teams that are really close to winning generally don't blow it up because they were that close to winning it. the Jazz for instance, didn't blow it up with Rudy and Donovan in their 2 successful years because they thought they could take the next step. It wasn't until they knew they weren't going to compete with that roster that they started over. I think Wolves are a top 3-4 team this year. So, if you are that close then why blow it up. Usually, you try to just add a piece here and there, and then hope young development gets better. You mention extensions and old players being the reason why they would blow it up, but if those are problems if they lose, why won't they equally be problems if they win?