I personally know a lot of porn stars.
It seems that the most successful ones are the ones that turn their names into directing positions and perhaps their own studios (small chance of that).
Sometimes after one gets long in the tooth, or blackballed from the industry or burnt out or whatever, they simply turn into overpriced escorts.
I went on a Pillage and Plunder cruise years ago (and it is EXACTLY what it sounds like) They had some porn stars filming a movie on there that was released on DVD. There were also some older stars out of the biz that were on board as "indepedent contractors". They were making per trick what the new guys were making per scene in the porn biz.