One reason why prostitution will never become legal involves the secrecy and the thrill that is required, either for the thrill to be complete or because the participants do not want any records of their activity that could be publically known. When married or prominent “customers” do not want to be discovered, then they will prefer the shadier and much more private forms of illicit and illegal sex.
Then there are those who crave the thrill of doing something illicit and illegal. The illicit thrill of illegal prostitution might serve as a release from the structured and restricted lives that people have gotten into or it might be a requirement for full sexual gratification to have relations with a perfect stranger in a prohibited way and at an inappropriate location.
Where prostitution is legalized, there are understandings that the customers are engaging in it and that they may even be regulars. But how, if ever, their spouses or significant others find out is the question. When it becomes clear, through credit card transactions or the reports of private investigators, the customer is probably in no better of a marital, relationship, social or financial position than if they had been caught in an illegal engagement, in a bad neighborhood and in their car.
Many prostitutes have made enough money through high end call girl, rent boy and escort services or at legal brothels to complete proffessional schools and to enter life at very prominent levels. They would have to confront the issue of professional prostitution showing up in their background checks, whether the background checks were done by licensing boards, potential employers or by potential mates!
Legalized prostitution would involve licenses, registrations, regulations, identity documents and a host of records that would identify both customers and workers in a host of ways that could result in the information being released to the public. The tax collections, fees and other costs of doing legitimate business would make prostitution far more expensive, driving less well off customers back to the alleys and side streets.
As a result, the registrations, licensing, oversight, inspections and records that legal prostitution would generate would serve as a serious impediment and discouragement to many customers and sex workers.
As a result legalization takes away the secrecy and the thrill of illicit conduct, so illegal and unlicensed prostitution would continue anyway, making legalization, at best, a far more costly and partial solution to an age old and pervasive social activity.