The point I tried to illustrate was that some prostitutes never wanted to be prostitutes. The whole reason this is a slavery issue is because people are kidnapped or duped by a false promise, and suddenly find themselves part of a "business" they had no intention of being in. How will we honestly know the people who are happiest simply being prostitutes and not the ones being trafficked around against their will?But why does the pimp/prostitute relationship exist? Because they need the pimps to enforce payment for them. They can't simply call the cops when a john walks out without paying. It's an underground business run by thugs. Eliminate the underground.
There is evidence that the prostitution business isn't simply filled with young twenty-somethings who've made their own descisions. I highly recommend at least looking at the problem of human trafficking before you consider legalizing prostitution. I mean some of the facts (which I picked up here) are startling. The latest U.S. Government figures indicate that between 14,500 and 17,500 people are trafficked into the United States for forced labor every year. The United Nations reports that United States is one of the top three countries to which people are trafficked into modern-day slavery. Look up any happy statistic to let you know that a good chunk of those people are going to work in the sex industry (I use the word loosely). You might argue that it's a business but it's impossible to tell apart willing participants, and what exactly brought them into the business.
What would become of current victims? That might seem silly too, but we need the ways and the means to make sure that current victims had a recourse, and you would need one hell of an application process. I don't think legalization is practical and I think it undermines the minimum standard we have set with the current statutes for sex crimes.