Top hundred worldwide is 'getting by pretty comfortably if you don't live anywhere significant, especially if you still qualify for food stamps or what have you', and it's competitive with what a career software developer will be making by 2030 or 2040 at the most.
Top thousand worldwide is already down to your $200 a month or so, and there are hundreds of thousands of people on these platforms. This is the nature of markets in an attention economy that scales worldwide: you're getting squeezed out by anybody anywhere, and if you're a niche (I'm a niche, but not alone in it: by now, there's another plugin dev who is pushing harder for money and making more than me, who is also Patreon-exclusive) then that limits the maximum size you can scale.
It's absolutely going to be the same on OnlyFans, Twitch, etc. As a job mostly this sort of thing is 'spend a bunch of money to operate at a competitive level, and then you don't earn anything to speak of'.
This IS free market dynamics in a state of maximum globalized low friction. Silicon Valley has spent a lot of time selling people on low friction interaction and discoverability. Tearing down the walls means you're competing with the girl with a perfect figure who's in New Delhi and has family money backing her (for whatever reason), and her competing with you means you work less.
When this seriously kicks in for the very software devs who've created this situation (and it may have been inevitable, let's not directly blame) and AI begins to compete with human workers at content creation and software development, the OnlyFans/Patreon/Twitch picture becomes the world, and at that point we've got some questions to ask about sustainability. A lot of these platforms are sustained by whales. I'd do substantially better (but would ruin my positioning) if I targeted whales.