We KNOW there are prostitutes currently that are coerced into it due to economics. Girls/women are brought from overseas on the promise of a cleaning job, and they end up as prostitutes. Happens here, happens in Amsterdam, happens in a lot of countries. They own the person who brought them over, they have to work at it. It also happens to runaways - they need money to survive, they get into prostitution.
Now there are women who aren't coerced by economics; they check out the job market, there are other things they could do, but prostitution's hours and pay strike them as the best way to go, so they enter the profession. That isn't coercion if they have other choices, anymore than choosing to be a cop rather than a secretary is coercion
However - they need the other opportunities available. If the only non-skilled job opening for women that pays a living wage is prostitution, then that could be seen as economic coercion.
But we're heading down the road of "word definition" and that's never productive.