#2. Goldberg normally only returns for one-off shows
After Goldberg's run concluded in 2017, there were only a series of one-offs or extremely short programs when he returned to WWE. The longest stretch he had post-2017 was last year when he faced and defeated 'The Fiend' Bray Wyatt in Saudi Arabia and was scheduled to face Roman Reigns at WrestleMania 36.
Reigns pulled out of WrestleMania and Braun Strowman replaced him without so much as a word said. Since Goldberg was never going to have an extended run in WWE with the Universal title, Strowman was the beneficiary, defeating the legend clean.
Even his Royal Rumble appearance was a one-off. It's hard to imagine him having a run that lasts longer than SummerSlam unless there is an actual plan in mind from WWE.
While they would prefer to have a top draw like Goldberg as the World Champion, it's not always feasible given his age and demands. He is a big, marketable name that only wrestles twice a year at most.
In 2019, he faced The Undertaker at Super ShowDown and Dolph Ziggler at SummerSlam. In 2020, he faced 'The Fiend' Bray Wyatt and Braun Strowman.
This year, it's Drew McIntyre and Bobby Lashley. 2021 is perhaps Goldberg's best year since 2016-17.