But rather that maybe the way he had done things and run a program for decades wasn't necessarily going to be the best way any longer. And that's really all.
I don't look at it as such a horrible reason for leaving. He's way older and pushing that pace is a lot harder. The context of that quote you showed is that he thought that next year's squad probably would have been a great team with another offseason of development. But, the players he had were making it clear that they weren't necessarily planning to be around without playing time assurances and desirable compensation. It can be a tough sell for a 74-year-old guy to want to keep pushing at his personal limits if his method isn't going to create a championship team any longer.