Mobile prostitution on wheels is probably a money maker idea. Illegal you say? Disrupt!
In that eventuality, yes, mobile service would obviously be at least as lucrative as van-based barber shops, probably far more so.
Prostitutes are still for the most part desperate immigrants, held hostage in various ways, and exploited by the companies that traffick them in and run the brothels. In other words, legalized prostitution still consists for the most part in paying money to shady people to be able to rape some poor girl.