Making things illegal doesn’t solve anything in the WWW, principally cos there isn’t a world’s jurisdiction and cos illegality doesn’t stop criminals, see what happened to the war on drugs… just a big failure.
Maybe attacking the problem from the root like educating people to avoid porn at all could be successful at some point but anyway this it’s definitely another problem of the hiperconsumist capitalist scheme.
Edit: I believe if it were illegal even the price of it will go up so it will be a bigger business at the end of the day.