first, I think the vast majority of twitter users won't be able to meet the requirements of the revenue system there. But it is a smart way to retain the content creators, which also keeps those those users too.
But yeah, you raise some good questions re: incentive to stay on nostr, as I think it z4ps aren't actually the main feature, similarly the rise in popularity in bluesky isn't about a revenue incentive.
As a somewhat side issue you could even argue that z4ps may have been implemented prematurely here lol, it's somewhat incentivised repetitive b!tcoin platitudes4pay maybe, and making a feedback loop of bad content which actually puts 'normies' off, not sure lolol. And I use 'normies' somewhat reluctantly, cos in this scenario it sort of implies anyone not interested in b!tcoin twitter in jokes as normies, and that seems not very generous lol. I think if you want to make an interesting and growing social media you probably don't want to incentivise farming for z4ps, it's not interesting and will put off newcomers, which MAY / may already be occurring, also not sure lol.
I think I've said it before but i can see potential for hope and growth in nostr being treated as a place content creators in the meantime point to in case their main accounts elsewhere get nukes, the same way youtubers recommend their Rumbles and etcs. And yeah those content creator people would see an incentive of potential revenue here. But a general audience don't really care about the sort of self-referential content about z4ps and whatnot. But again, this is nascent but I'd like to fast forward inti the future and see z4ps as a normal background function really lolol.
yadda yadda, what a mess of thoughts lol, some of it might even be clear hopefully.