I absolutely think it would be less profitable.  Simply put, often times the money is good because of the assumed dangerous nature, and because it's not something a lot of women will do.  On a whole, even in legal aspects, not a lot of women do sex work.  Were it really to be just like any other job, I think more women would, which would increase the number of people in the "sex work force" as it were, which would drive down fees.  It's true with any business: competition lowers prices.  I don't see why the sex business would be any different.  And while women might not turn to it in droves, more probably would turn to it.