"...the young ladies I have spoken to dont believe they are performing a "useful service".."

Well now... there's a nice survey! I'm sure all Indians walk in single file, because I saw an Indian once, and HE was walking single file.

I will try ONCE more to make the point. There are two issues: 1) Should it be legal and regulated as long as everything is fair & consensual? 2) Are there serious problems in society that make much of it degrading, dangerous and enmeshed in drugs & other crime?

Why can't both be true? Of COURSE we need to "... be concentrating on constructing a society where there is no longer any need for women to sell their bodies to strangers."
But..what if we GET that society or close to it? What if 'strangers' are not involved? What do you call it if there is an 'understanding' that if HE provides dinner & a movie, SHE provides sex? Yeah, there's a difference between that and a cheap hotel and streetwalking...but you & I both can describe situations where it's very hard to draw a line.
It should not be necessary or common, but it should not be automatically condemned, because there ARE women who consider their 'special talents' to be salable skills, and some who genuinely DO enjoy the 'job'. If this society were not so hung up on artificial definitions of what 'nice' sex is about, there would BE far less sad situations.