porn in printed form was akin to the Bible in that it was one of the first things that benefited from and was made possible by the Guttenberg's invention. Guttenberg died in 1468. Since then there has not been a population crisis, right?

Conclusions?

Unless you claim that it is something specific to the modern delivery of porn via high definition streaming, but then you need to make a point of it when you write. Images that might be considered pornographic go back in history (further back than 1468). Still no population crisis (or, the crisis of over-population, but not under-population). How do people reproduce? Via vaginal sex. Men orgasm inside women, and so it goes and the species is perpetuated. regular porn has not been able to do away with it. If you claim modern porn is different from regular porn, then sure, but you need to state it. As you put it, your claim is indefensible.

Also, you said that porn is manmade but masturbation is not manmade.

This makes me curious - so who "makes" masturbation? Who, indeed, makes masturbation? Aliens? Gods? Animals? Or, does it, perhaps, grow on trees? Were you talking of masturbation to endogenous fantasies, perhaps?