#1 The Boneyard match did not happen in front of a live audience, and The Undertaker wouldn't want that to be his legacy
Every WWE Superstar lives for the roar of the crowd and The Undertaker is no different. Here is a man who has sent shivers down many a spine from the time that he made his debut because, from his entrance to his trademark finisher, everything The Undertaker did was truly a class apart.
For someone who enjoys such a connection with the WWE Universe to call it quits after a Boneyard match does not make any sense at all. The Undertaker needs to call it a day in front of a packed audience when things go back to normal again so that he can finally say goodbye to the fans.
Maybe the match happens against King Corbin. Maybe there is a dream match between The Undertaker and The Fiend where he can finally put over the next supernatural character in the sports entertainment business.
I can't imagine The Undertaker retiring after the Boneyard match.