Yea but like, in the older games you had to do certain things to unlock the characters, and it took time and effort for some of them.
If I recall, in 4 all you had to do is play a small number of matches.
(unlockable characters in smash for Wii U)
In smash 4, you could unlock characters by completing their challenges
or playing the required amount of versus matches.
There's only 8 unlockable characters though. In SSBU there will easily be more than 50.
Considering the amount, they might drop the vs match requirement and just have them unlockable via challenges to make getting the full roster an adventure, but a lot of players just want to get the characters fast due to tournaments and such.
I think a good compromise might be to do unlocks via a Subspace Emissary-like adventure mode, where in order to get the characters on your team, you have to meet them in the story.
That would be awesome, and it would give players a straightforward way to unlock characters.