I was surprised why OnlyFans is so popular. All in all, there is no shortage of free erotic materials online ( https://observablehq.com/@stared/tree-of-reddit-sex-life for a small subset). I got an insight from "The Surprising Psychology Of OnlyFans Simps by Charisma on Command" ( https://www.youtube.com/watch?v=auG2E53dFas ) that subscribers buy attention rather than sex .
That's how the Minitel[1] got popular in France. They had these chat services where one paid per minute to chat with "women in your area" (It was mostly male operators handling multiple conversation simultaneously[2])
These services have always existed, and were always in demand, the only difference is technology and business models.
[1] https://en.wikipedia.org/wiki/Minitel (basically the french version of the internet, ahead of its time)
[2] In French: https://www.nouvelobs.com/rue89/rue89-rue69/20120629.RUE0957... "My name is Jean-Marc and I was 'female moderator' of erotic Minitel"