Plus, lets not forget family is the most important thing in Doc's life. Money isn't a huge issue for him, he's been well compensated and I'm sure he's managed it well. For Doc it has to be a passion every year; and taking a year or two off between jobs is probably very appealing.
I don't think he's doing us a favor in his own mind, I think he's weighing his desires and coming to a decision. It's not like if Doc walked away he'd have to do penance as an assistant somewhere (like Lawrence Frank or Flip Saunders), Doc just has to say, 'Im ready to coach again, and take his pick of what will assuredly be over a dozen offers between college and pro teams.