I feel (as the uninformed choad I am of course) that when he 'retired' he both realized A) (power-wise) he loathed seeing the product go on and prosper without him at the helm as WWE was his baby, even if it was family running the show, and B) (money-wise) with the lawsuits & legal troubles popping up he probably felt he could make more money if he sold the company, than he would make in however much time he had left running it himself with those aforementioned legal issues causing problems and the board/investors possibly not wanting him around much more.
TellumSiege