He says that he won't retire until he once again becomes undisputed heavyweight champion of the world.
Never he still believes he can do it again, he needs to fight for a small belt IBO or something and call it quits. Wlad will throw it away after his next defense (IBO) So he can manage his way to fight for it.
I wish he would announce it right now, but he'll have a few more fights probably. I sure hop he doesn't though.
He like all great fighters or athletes that were once idolised, they miss the attention, the roar of the crowd , the adrenaline, The adolation.. Even the $$$$$$$$$$$$...
He'll probably end up fighting in Colorado or something. Or, as others mentioned, fight for insignificant belts. Remember: Mitch Green was the World Boxing Syndicate champion after beating some guy with 94 losses on his record.
It wouldn't be worth at this point. I'am a huge fan of Holyfield but he needs to sit back and retire.