> If we are talking about voluntary prostitution in a country with a welfare state then does it count as coercion if the person chooses prostitution over a minimum wage job because it pays better?

Here's an interesting question for you: is the public entitled to make prostitution illegal,[1] on the basis that they don't like the sociological implications of selling sex becoming an alternative to getting a minimum wage job? I think they are quite entitled to do that.

[1] Though I prefer how Sweden does it: to make buy sex illegal, but not selling it.