I believe that a piece of this puzzle is missing.
Hooker economics on a SHMB are an entirely different animal from Hooker economics OFF a SHMB.
Here lately, at least in Dallas, many ladies have been raising the rates to simply cut down on the riff-raff. The board climate is changing and there are many ladies who would rather just up their rate than deal with some of the newer gents that are coming to the party.
Off board rates among those who simply use EROS and a couple of other venues have been increasing at a steady clip for the past decade. A better study of hooker economics would be to evaluate the pacing with inflation off board-- on board has other factors in play that can't be ignored.