That's the object of economic policy. If I make widgets and no one wants to buy them, I would be deemed by the marketplace to be essentially nonproductive. Now, supposing I was a madame running a brothel, and the economy turns down and my middle-class clients can't afford to come by. So my business is failing and my girls are nonproductive in the marketplace. Anything in the economy that satisfies the tastes of individual Americans, individual citizens, is productive.
Prostitution is productive.
What you will see happening, the more the institutions of government are arranged in a way that will permit people to fulfill their potential, their legitimate potential, is less prostitution, less drugs, less pornography, even abortion. All of these come as a result of the impoverishment of the economy. They're a reaction against the forces of Malthusian darkness. It's not a matter of Keynesians or Friedmanites. If you believe in progress, then you see a whole set of social attitudes developing because you are expanding opportunities for individuals, even though individuals are multiplying like mad.