It seems like you're using something like the efficient market hypothesis without looking at the evidence.

I'm not a huge porn consumer but I've seen enough and know enough of the industry to say you're basically wrong, at least wrong as far as any "cottage industry" for porn with decent production values, acting or "sincerity" goes. The key thing is decent production value in a movie can't be created in home-grown way, it requires serious dollars. Oppositely, there are actors and there are "adult actors" and the two jobs are considered very distinct (in the way that receptionist and sex-workers are segregated and should be segregated, as mentioned on another thread).

But hey, prove me wrong. I'd love to see a counter example.