Purely anecdotal, but I saw some talk show interview with an aging female porn star who'd retired from on-camera to handle casting and production duties and they asked her about male porn star salaries. She said the pay isn't great for guys unless you're a "name recognition" top-tier male porn star (probably that'd be/have been people like James Deen, Bruce Venture, Lexington Steele, or - God forbid - Ron Jeremy over his many years) or "you do gay porn", then "you can do okay money-wise as a guy, in gay porn".
I remember this and like you, had always heard it repeated that the better compensation in straight porn is for the women.