Why is Kirby’s Smash stage representation only ever from older games?

I really don’t get why Smash locks in on “old Kirby” when it comes to stages especially.

Like take Smash 4 on the Wii U. For Mario, we got NSMBU, Mario Maker, and Galaxy stages, for Metroid we got an Other M stage, for Pokemon and X/Y stage, for Pikmin a Pikmin 3 stage, and heck even Game & Wario got a stage even though no one remembers it.

But for Kirby? The Great Cave Offensive. Super Star at that point was about as old as methuselah, and there were a bunch of other games on home consoles that came in between. Nothing for Return to Dream Land, Epic Yarn, Rainbow Curse.

And it’s not like that’s a one off. Every other Smash game has done it or something similar just forgetting recently released Kirby games.

Smash 4 on 3DS wanted to mostly reference handheld games, but there was nothing from Mass Attack, Triple Deluxe or Robobot. Only the Game Boy Dream Land stage.

For Brawl, no Air Riders, Amazing Mirror, or Squeak Squad stages. Only a Super Star stage

For Melee, nothing from Kirby 64 or Tilt n’ Tumble. Just Green Greens and Fountain of Dreams.

And for Ultimate? Nothing new at all even though Star Allies came out just a few months before.

Is there a reason for that? I feel like since Sakurai is in charge of Smash, Kirby should get as much new game representation as Mario or Zelda, but they always seem to fall back on “old Kirby” rather than “new Kirby.”