If you want to call my following rebuttal biased because of my sig, then so be it but I'm leaving my own thoughts into this.
In his 22 year career with the WWE, Undertaker has rarely been about himself. I don't know the guy and I don't know what kind of a person he truly is but with the things that he's done and with the way he's contributed to the company, I doubt he's really been about himself and now that he knows that he's a not necessarily a consistent player, he's more than willing to do what's best for the company and that's building up the streak. That's not to say that he hasn't tried to have it ended a couple of times but guess what? All of the streak ending candidates have turned it dow so you really can't say that he's coming back once year for himself and for the sake of "basking in glory".