Longstanding urban legend is that Austin had told Vince he would work a reduced schedule and have surgery after WM 2000, but it was predicated on the understanding that Austin would would keep the belt and be presented as world champion until then.
Then Vince, in the fall of 99, got serious about pushing HHH and Austin wouldn't drop the belt to HHH as Vince got upset that he had to use Foley as a middleman and Austin waited right before Survivor Series to tell everyone he was getting surgery now not later, thinking HHH and Rock would flop as top guys and Austin would return a year later, his position as #1 Guy assured.