Described in full detail by this VGC article.

Sakurai says Ultimate is the ultimate (pun intended) collaboration in gaming, and that if there are more Smash Bros. games, then there's no way this many fighters, and series, can be represented again. There are still requests all over the world for new fighters.

He added that, as long as there's an opportunity to make more fighters, he wants push the record further.

So he's saying there very well might be more Smash Bros. games because of all the requests for new fighters, but not all fighters from previous games would come back in subsequent games?

I like that the opportunity for new Smash games is still there, but if not all of the previous games' fighters can come back, makes me appreciate Ultimate a lot more.

How do you feel about this?

I mean, personally, it is a bit of a disappointment. I understand if they can't do all of the third party characters, but every character that Nintendo owns should return, and build on that roster.

The game has 70 plus characters with guests from 6 other companies one of which is a competing platform holder it's a given that future games may not achieve the same.

Like how we may never another Avengers Endgame?

I can hear the bellyaching already when the next title comes

TBH I see this as an absolute win. I really dont like the gigantic roster in fighting games. Knowing how to use all characters allows one to play more competitively when playing against them and that its pretty darn hard in SMU. That is the one gigantic plus of the original SM64 (which remains my fav).
SMU has what? 70 chars? I mean, I dont know if we need characters like R.O.B. or Palutena or Corrin in the game.

I really hope that they don't remove characters with the next one.

But I like those characters. -_-

Of course. The next Smash Bros will be a reinvention of the franchise. 70+ characters is too much start with.

Who's saying we'd start with 70+ characters?