My point is that this is why we've seen the Spurs continue to be successful long after most people assumed they'd be fading, while the Celtics have declined and find themselves with a team that has very little depth.
I don't get your point at all. I doubt you are trying to argue that a core of Gary Neal, Kawhii Leonard, Danny Green, DaJuan Blair, and Tiago Splitter are going to keep the Spurs in title contention without some more help after their big three retire.