Prostitution seems to have always been a privately held shadow marketplace. Where the exchange of these physical goods only take place after various forms of verification have taken place. It has its own economy. And yet, these employees lack the benefits, rights and protections as other workers have.
Though the phrase of it being recognised as the oldest profession didn’t catch on until after WWI. The world’s oldest profession has the best images that come to mind. Additionally, it’s still a subject that must not be named.
Sex work is still something of a secret that we hide under our beds and in our closets.