i have wondered about this a long time. the population changes from season to season but there was a time years ago where a couple worlds complained and had new recruits added, but i felt that the steady-state population of recruits was down enough to notice across the board. i'm kinda fairly skeptical that recruit gen does generate the 'right' number of recruits, based on whatever its supposed to do, or at least that it didn't break some time years ago. no evidence though. there were a handful of folks posting some anecdotal stuff but i kinda was always too lazy to pay enough attention to contribute.
its probably all fine, but i definitely would not be surprised if its not.