The government is complicit by keeping it illegal.
If it were legal, it could be taxed and regulated like anything else. Most people are OK with letting others do what they want with their own body. It's certain puritanical, tyrannical, authoritarian and powerful government factions that don't allow that.
I think it depends on the government. If the taxes or regulatory fees on legal prostitution are too high, it can create a black market similar to that of tobacco or pharmaceutical drugs.
If it were legal, it could be taxed and regulated like anything else. Most people are OK with letting others do what they want with their own body. It's certain puritanical, tyrannical, authoritarian and powerful government factions that don't allow that.