Simple. They start slowly. They sign up for Tik Tok, quickly figure out that when they wear something "naughty" they get more views... Then they start wearing naughty clothes more often in their videos until someone says "If you had an Only Fans I would pay to see videos of you". They create an account, dip their feet in, slowly use their Tik Tok (or Instagram account) to promote it... Suddenly they making $10k a month. They quickly figure out if they put more effort into it... They would make a lot more money.
Texas Thighs is a great example. She used to clean houses. Her husband took a picture of her working out, put it on her Instagram, and suddenly she had 15k followers. A year later she had 100k followers.
https://www.nbcnews.com/tech/interne...g-ba-rcna23449
It'a amazing actually. Twenty years ago you needed a "webmaster" to do this - someone to take pictures and videos, edit them, build a website, set up billing, market the site, handle the affiliates... now a model can do it all on her own with a cell phone.