It would be interesting to know how many established escorts have ended up exiting in favor of OF and the like. I agree that there are a lot of newish RM ads which are likely just advertising for OF business, or effectively being a screen process to identify clients willing to pay a big premium for an escort.
I have a lot of respect for successful escorts. As a rule, they've managed a level of self-discipline and social skill that I would have serious trouble matching. I don't want to appear dismissive of guys who are solely in the online model category, but it seems like escorting is the more challenging job.