I'll admit that the last few sentences of your post make good points but the first, at least when you get outside (relatively) cossetted First-World-problems territory into the parts of the world where most people and thus most prostitutes actually live and work, strikes me as simply ludicrous.
I don't want to have language about this further right now.
My job from 2007 to this July, which I suppose I can now talk about, was dealing at a government level with victims of crime including reading full statements, police reports and social service reports from victims of childhood sexual abuse and adult victims of sexual abuse. I have probably looked at a tens of thousands of cases in that time.
Sexual abuse of prostitutes is under reported for two significant reasons, with the prime reason being that fact that it is usually a statutory offence. Secondly, there is a strong link between people who have been victims of abuse prior to or outside of solicited sex, of which 'payment' numbs that particular pain to the point it ceases to 'feel' like abuse. That's what I mean by there not being a distinct set of economic conditions (i.e 'being poor') to prostitution. Furthermore those who solicit, their clients and even wider society and law have created an artificial differentiation between 'low class' prostitution and 'high class' soliciting. From experience, those who suffer abuse within that model (as there is 'choice' and 'self regulation') tend to be more willing to reporting the abuse and having a proper response by the authorities.
Continued criminalisation of prostitution perpetuates this division. Indeed, why would a high class call girl want to be
equal in law with decriminalisation in place rather than remain 'classier' with continued criminalisation that is less intrusive for them than those on the street? And that's where, with everything, power and protection is an issue much more than money.