The things that drive people to "voluntary" sex work is often the same stuff that everybody with a "voluntary" job contends with: education, rent, food etc.
I do think an obvious step is making sure those needs are met by society to reduce coercion.
As for the necessity of jobs, I don't think sex workers, drug dealers or butchers should be jobs that exist, but I would not outlaw those people for practicing jobs that I think shouldn't exist. I don't think those jobs should be illegal.
Banning sex work does little but create another power imbalance that predators use to exploit sex workers similar to how criminalizing drugs leads to more exploitation.
As for sucking dicks, I would rather do that than perform surgeries or butcher animals. If folks are only getting $20 bucks for a blowjob that seems criminally low.