Six years sounds extreme... I could probably buy that Vince told him he was gonna be a top guy for a long time, but I don't see Bret having a continuous Bruno/Backlund type hold on the title all thru the '90s.
It makes me wonder how many of these promises people say Vince gave them were to even be believed or be taken with more than a grain of salt. Because wrestling can be unpredictable when it comes to who gets over, who leaves or comes to the company, the changes that can take place. You can be slated to win this or win that, but let's say somebody else comes along and catches fire or your push doesn't go as expected- I can't imagine it's not subject to change.