ok guys... after a decade I've got it. This is fucking it:

The only reason prostitutes are able to sell sex for $50 dollars for 30minutes is because ALL women are prostitutes. If ALL women weren't selling sex, then it would be impossible for professional prostitutes to undercut them.

Just think about it for any other commodity, if I were standing on a street corner selling water for $50 dollars a litre, but every other man was carrying an unlimited supply of water and it cost them almost nothing to give it away and they even profited from giving it away.... how could I sustain my water selling business?