Fun fact, I've never played Fortnite. Or any live service game ever.
I'm not saying that Sony could do it with such a small team. I'm just saying most of these games didn't start out with as large of teams as they currently have. I expect that the teams will have something in the 150-300 range before they launch, and if they're successful enough that could very well bloom out to 1000+.
I guess more interesting, is what happens if they're not successful. Does the studio move onto another live service title, do they get shut down, or could they move onto a single player title instead.
I really doubt most of these titles are using 1000+ people. How much is respawn? How much is bungie? How big are psyonix?
Even if launch isn't successful, updates and even changing the business model could turn the game around.
I guess it depends on the studio, ND would certainly live and return to single player games, even if successful, I could see this being their only GaaS game for for the next 5-10 years.
A studio like haven? I doubt sony paid much for them, I could see Sony giving them another chance, specially if the game is good. Sony seems to be more concerned with quality over sales. And by quality I mean reviews. I think they have the conviction that if a team is good and makes a good game, even if it bombs, they have quality to make another game that can be successful.