I 'm less surprised by this in retrospect. In 2015 - Season 1 - we had Facey and Angelino (anyone else?). I think that's it.
Thing is, I think we can do and have done better than Facey within the MLS roster and cap rules. Angelino is better, but we only had him for a half season because of his and Man City's priorities, and both of those priorities will always take precedence over NYCFC for any such player. I don't think many coaches including PV want players rotating in for 1/2 seasons and as you note even one full season is borderline. I would not categorically rule out 1-year loans by any means - they can be very useful for all involved - but you only want so many.
Also, while this never quite reached a consensus opinion, I also know I'm not the only one who thought Angelino made it clear he thought he was better than this team and league and didn't really want to be here. That he was mostly right doesn't mean you want someone who has that (apparent) attitude hanging around. I can't really blame young guys who sign with Man City who think a stint with NYCFC is not their ideal assignment, but I don't want NYCFC to repeatedly deal with the Jamie Tart* growth path either.
* Yes, everything comes back to Ted Lasso.