The bigger issue is that there is a different model for the granular micro-monetization of low-rent celebrity: it’s called being an influencer and it’s mediated by TikTok, not by Cameo.
And the low rent thing isn’t a diss: it’s moving upmarket faster every year.
Now that you mention it, is it weird that social networks haven't moved into this form of monetization? Why does Instagram not have an influencer marketplace where you can pay for a post from a popular account?
Is it because of some nebulous "ick" factor that would cheapen their brand? Or is it simply because they can make more money by selling advertisements in the middle of the feed?
There’s nothing nebulous. Top-tier influencers get VIP treatment. This is the same as Sinatra’s crew in the 1950s.