Generating porn is easier and cheaper. You don’t have to spend the time learning to draw naked bodies, which can be substantial. (The joke being that serious drawers go through the draw naked model sessions a lot, but it isn’t porn)
The models art schools get for naked drawing sessions usually aren’t that attractive, definitely not at a porn ideal. The objective is to learn the body, not become aroused.
There is a lot of (mostly non realistic) porn that comes out of art school students via the skills they gain.
