en.wikipedia.org/wiki/Gay-for-pay
The overwhelming majority of consumers in the adult industry are men - straight, gay, and everything in between.
I would imagine only a really tiny percentage of good looking heterosexual male SPs could establish a female customer niche, especially in the swinger/cuckold scene. Outside of that I don't see sex work being viable for men unless they entertain men to some extent.
Our horniness makes the world go around!