So it looks like it was all Brock's idea to get creamed by Goldberg at Survivor Series and embarrassed by Goldberg in the Royal Rumble, so that Goldberg would be at his strongest when Brock finally beat him at WrestleMania 33.
According to The Wrestling Observer Newsletter, Lesnar always went to bat for storyline elements and match bookings that were designed to make Goldberg look strong. After all, Lesnar knew he was was winning the feud with a decisive victory in their WrestleMania match, so why not get the extra rub from getting revenge on the guy that trounced him so badly four months prior?
Apparently, Goldberg put his trust in the long-term process, too. He knew it was a Brock Lesnar feud and WWE creative wouldn't dare meddle in their storyline. Brock's sway at the company is so great, that would never be allowed to happen.
The WON notes that Goldberg’s WWE contract has officially expired, but the deal still allows them to sell Goldberg merchandise for an extended period of time past the contract's end. While there are still thoughts about bringing back Goldberg for another brief run, since his first was so successful, there's no rush to sign him to a new deal at this time. The feeling is that nobody else could possibly the money that Goldberg made on his most recent run with WWE.
Goldberg returned last fall for his "one last match" with Brock Lesnar at Survivor Series, won a shocking squash match, then stuck around for "one last title run," eliminating Brock from the Royal Rumble before getting eliminated himself by the Undertaker. He got a shot at the Universal Title anyway, defeating Champion Kevin Owens in 26 seconds at FastLane, and went into WrestleMania 33 as champ. He and Brock settled their feud with a fun, finisher-spamming match that lasted nearly three times as long as their Survivor Series match.