16 or 17 as kiddy is not my definition (though I did say the age of 18 earlier), it is the legal age as defined by current law.
Those currently producing non kiddy porn would not switch to kiddy porn. They would continue with what they are making as there is a HUGE demand for it. No need to switch to a product with less demand, and far harsher legal penalties.
You say that most porn is already legal. Well, yeah, kinda. Not legal like milk is legal, though.
If porn moves from the adult bookstore at $69.95 per video to the local 7-11 at $14.95 per video, porn producers will be looking to invest in any remaining high profit (illegal) business.
In my opinion.