WWE never gave us the Goldust vs. Stardust match we (and they) wanted to see but it's finally going to happen in Las Vegas when All Elite Wrestling hosts the Double Or Nothing PPV.
Now, Dave Meltzer has revealed that Dustin asked for his release on January 19th and was then granted that along with a 90 day non-compete. However, Vince McMahon didn't want to let him go and it was Triple H who ultimately talked the WWE Chairman into allowing him to leave the company.
It's been a long time since Dustin did anything of significance in WWE and it's easy to see why he wanted to leave and join All Elite Wrestling.
What led to Triple H pushing for him to be allowed to go is hard to say but he's probably thinking longterm and would like to remain on goods terms with the Rhodes family in case they one day return to WWE (bear in mind that The Game was also incredibly close to their father, Dusty).