Very possible that's happening but the amount of replies also reflect this. You have an entire world of replies under the big NOSTR profiles that don't exist to the same extent on Fedi, and most of it isn't spam.

If I had to guess, NOSTR probably has less users, but a more connected community, so you get the experience of a much bigger network if you talk about the right things. Fedi technically has millions of users but bc the cliques are somewhat insular it feels like a few hundred max, whereas you could never make that mistake here.

Ultimately sheer numbers don't matter but it's interesting, anyway.