But this is becoming a huge problem with a lot of Nintendo studios or affiliates:
Camelot
Retro
1-UP
Nd Cube
NST
All fit the diminished capacity category you describe. I mean look at AlphaDream, they were churning out Mario & Luigi RPG after Mario & Luigi RPG until one day people got sick of them and they collapsed soon after. Variety is very important for a studio's survival.
Calling it a 'huge problem' is a massive exaggeration. Even with their relatively low headcount (which is unconfirmed - the ~50 person headcount is from 2010, so is badly out of date), Camelot's most recent game was their most successful yet. That's hardly a harbinger of impending doom.
ND Cube will have produced two titles on Switch as well as the Animal Crossing mobile game and a 3DS title in the last 3 years, so there are hardly any signs of trouble there. Plus, if we take the out-of-date figure as indicative of Camelot's current headcount, ND Cube are twice the size of Camelot and a similar size to other Nintendo partners like Next Level.
Now Retro must obviously have had some problems, but we can't put that down to headcount - it could be bad management, or something on Nintendo's end that led to projects being cancelled. Stating their situation is somehow similar to Camelot not producing Golden Sun is nuts - Retro are lead developer on Metroid Prime 4, so whatever's happened over the last few years, Nintendo still trust them. We don't have any information there to say the future of the team is in doubt, because the future of the team involves finishing a high-profile project from a long-running Nintendo franchise. You don't get that investment if Nintendo think you're going to fail.
As for the other two, 1-Up have been an assistance studio for close to a decade now - since Super Mario 3D Land on 3DS. That's why they rebranded from Brownie Brown to 1-Up - they're an assistant developer, not a project lead studio. NST have also been on smaller projects for over a decade, since Nintendo gutted them following the whole Project HAMMER debacle. Neither company needs to be that big because their purpose isn't to lead development on individual projects so again, comparing either of them to Camelot doesn't hold up - Nintendo made the decision to downsize NST a decade ago.