Don't you? The past few years have seen a spate of "high-class call girl" memoirs. Unless you want to make the novel claim they're all fabricated, or try somehow to argue they are negligible, that would seem to suggest that your second claim here is not accurate.
"People who see prostitution as something which exists on a number of different, exclusive and distinct class-related levels are people who do not understand the interrelated nature of it, and some of the people ignorant of the shifting nature of prostitution are actually prostitutes and prostitutors themselves."
Absolutely, which is why I would like to hold people who choose to purchase sex accountable for their human rights violations. They have agency; they have the choice not to purchase sex and yet they do so anyway.
If it were about freedom, you would see people of all economic conditions choosing to prostitute themselves. But you don't.