Because so many people advertise it as an easy way to get money, and not SW. So, people approach it totally differently than they should.
OF has absolutely ZERO internal search options, so the only way people find you on that platform (no matter the kind of content you make/how good it is/etc) is through social media. So, if you're not skilled at marketing with a huge social media platform already, you make little to nothing. (that's just talking about subscriptions, & not including PTV, or sexting, or customs, etc)
The thing people mistake when they do things like make an OF is that part of the appeal for customers is the parasocial aspect of it. They want to feel like they're interacting with someone they know, someone they care about.
OF is not PH, they're not going there to get off real quick and close out their incognito browser. They're logging on to talk, to engage, & to feel like you, yourself are the one who is getting them off. Otherwise they'd just log onto PH.
If you approach OF like the only thing you do is make porn, then no one will care. the catch? If you don't make porn accessible to them once they sub to your OF they'll complain.
It's one of the reasons why I don't use OF tbh, because it's too mainstream, and not kink friendly. but also because I don't just make vanilla porn. I make mental domination, denial, worship, no sex, but goon, look into my eyes, but don't ever cum porn. And unfortunately OF is too mainstream for the random person to just happen upon your work without me having a substantial social media following.
Who knows, maybe if y'all get Me to a million followers I'll make one again lol! (get it, cos that's literally never gonna happen)
But the truth is that it's not easy, and that's the hardest pill for people to swallow about SW! Because they think if they do it they'll be rich quick, because someone told them it works that way and because they think SW isn't work! But they don't know what SW is, what goes into it, or how much work it takes to make enough money to survive on just SW alone!
You kinda have to care a lot about what you're doing for it to succeed, and even then it still takes a long ass time!