Why doesn't vince like foley wrestling in matches?

Ever since taking the dive in that cage match against the Undertaker, he has been semi-retired in the WWE. Except for his role as SmackDown Announcer he was generally there in spots. He'd just come and go. He has never been a steady part of the WWE after that fall, though. (EDIT: Or rather, he was not contracted for 1-3 year periods like others. And was offered book promotions and other incentives, and cameos such as his appearance at William Regal's WWE Idol.)