They all died in the war

They wont even put falcon in mariokart, after they took his tracks, his music and his ride.

Well, if I were to guess, it has to do with Nintendo's entire "securing the brand" thing back in the late aughts to late 10's. You know, when every single mario game was basically just New Super Mario Bros? When Paper Mario started to really blow? And the party games forgot their entire gameplay loop? I dunno why, but for over a decade Nintendo played everything super safe with the Mario series, there were like 3 new enemy types each game. People like Scott the Woz and Arlo put it much better than I ever could (simply watch 7 hours of Wii U reminiscing), but the point is. Nintendo is scared of a console or franchise doing bad, and they often come to the wrong conclusions as to why their projects fail. The Gamecube wasn't out competed by the PS2 or XBOX cause it was a bad console, but because it didn't offer the conveniences such as dvd playing or catering to the teenage-male-dominated market Nintendo helped to grow the previous two decades. (Talk about getting hoisted.) Nintendo went on to make a more convenient and popular console, sure, but their conclusion was also to play it waaaaaay safer with the Mario brand. Aside from the Galaxy games (all 2 of them), the Mario games lost a lot of their personality. Just look at the travesty that is PM: Sticker Star , or the blandness of NSMB U and NSMB 2. So a lot of their previous decade's catalougue was very lacking in both old "off-brand" characters and new fun ones. And probably for the same weird reasons, Nintendo has an aversion to GC era characters, cause it was one of the worst revenue-wise for Nintendo aside from the Wii U (Which was also created from the same unnecessary caution, wacky, eh?)

Geh, enough ranting, I gotta go get back to playing Mountain of Faith on the Windows PC! (Why don't we have any Reggie Fils-Aíme emotes)

woke

they introduce 3 to 10 new bit characters every game. they can't all be part of the core cast in a series with so little actual plot.

I miss them

I miss all the wacky characters from Superstar Saga... The hoohoos and the beanish were the best. Too bad Fawful's dead after Inside Story.