Oh and a sequel to Kirby Air Ride directed by Sakurai was not something I had on my bingo card. Especially since he literally left HAL after the development of the first game, many speculated the troubled development of that game contributed. I guess either the development of the original wasn't as bad as some thought or even if it was, Sakurai really wants to make a sequel to that game with the idea's he couldn't do at the time or new idea's he's thought up since. Seriously, I doubt Nintendo or HAL would have approached him to make this game since the original wasn't exactly a massive hit, so Sakurai himself must have really wanted to do this, and after the massive success of Smash Ultimate, they'll give him a blank check for anything. Similar to how they let him make Kid Icarus Uprising after Brawls success.
I think part of it is that Sakurai said he didn't want to do more Smash so I think him going back to Kirby makes sense and with the technological and gameplay advancements since the GameCube era there was going to be some new ideas.
Plus with Smash 2 being able to play compatable Switch games and the possibility of Switch 2 Edition games I think it is more likely that we get Ultimate playable on Switch 2 and/or a S2 Edition version. To give Sakurai a chance to recover from the grind of the Smash series for maybe the following generation after Switch 2.