Bill Goldberg really played things perfectly. When he first agreed to return to WWE, there was no question he was losing. He was happy with the money and understood if he was one and done, it made no sense to win. But as Vince McMahon kept pushing more and more for him to agree to more dates, and Goldberg kept resisting, it turned into a situation of Vince wanting something he can't have. Goldberg was absolutely adamant that he wouldn't commit to anything further until he saw how he felt after the match.
As we reported exclusively on Wrestling News World Premium, it wasn't until the week before the match that Vince finally got Goldberg to crack a bit and at least consider signing on for further appearances so that Vince could book the finish with knowledge of whether Bill would be back or not. With Bill concerned about how his body would feel after a grueling match and if he'd want to risk being locked into doing more even if his body made him feel like he shouldn't do more, Vince came up with the idea of Goldberg squashing Brock and saving the more grueling match for later on. Which alleviated most of Bill's concern with signing on for more appearances.
Basically Bill feels he has at least one more match in him, but won't know until after that match if it's the only match left in him, so Vince essentially punted by putting together a situation where Bill didn't really work a match at all at Survivor Series, can have a limited appearance in the Royal Rumble, and then save the real match for WrestleMania. Then after WrestleMania, Bill can see how his body feels and if he wants to continue.
Once Vince presented that scenario, it was really a no brainer for Bill to agree to extend his deal beyond Survivor Series. Things had been a little tense before that because Bill absolutely did not want to sign on for anything further until he saw how he felt the day after, but once Vince pitched the one minute match, they were able to get a deal done pretty quickly.
As for Brock Lesnar, who is all business and couldn't care less about winning and losing, when he found out he'd be getting his PPV main event pay for a one minute match, he was all smiles as well.