Why wouldn't they just keep making the same porn they were making before? Their profit margin is less, but they have much more financial security and no fear of going to jail.
In any event, what type of illegal porn are you talking about? Kiddie porn is pretty much the only stuff that's truly illegal. Some regular porn producers cross the line to obscenity, but that is a very small part of the market.
Well, this whole line of argument started with the hypothetical of all porn being illegal (post #46). I contend that as more porn becomes legal, more porn producers are switching to kiddie porn.
I've never heard or read so much about people being arrested for making or possessing kiddie porn as I have in the last 5-10 years. I cannot believe that the number of producers and distributors have remained constant. If they have, they're working overtime.