Both are having physical problems, Shaun Michaels having Back problem and Stone Cold Steave Austin having Knee problem you can't expect these guys now in square ring.
Undertaker wanted to stop after 20-0 WM.
But his streak match is a star attraction of WM, and WWE/Vince didnt wanted that... thus he is only fighting 1 match per yr.
Micheals, Austin are both old, and have badly battered their bodies, over d yrs.. competing in d ring. :gn
Jeff hardy has drug problems, he is unable to clear the WWE drug test... TNA on d other hand, are not strict over drug abuse.
Rock is doing movies. goldberg is just not interested in anything