Porn isnt very profitable for men unless you become a superstar by a mix of hard dedication and chance, there's no wonder why so many men are reluctant to enter the industry. Actually it has historically had a social stigma, as if porn acting was a job for outcasts and gangsters. I have seen a number of really well endowed men (I am not giving measures, as I dont usually carry a tape on my pocket) and they werent even interested in making solo videos, let alone partake in proffessional porn shootings. Most of these men didnt even pay much attention to their cock size so it sounds crazy that their dongs should determine their careers. They have normal jobs, normal families and normal lifes, as any other regular folk.
Of course there are bigger cocks on the streets than in porn. Its the same about super sexy women with oversized tits or whatever: thay have no interest at all in becoming porn performers. In your city there are hundreds of super sexy women who by no means will become porn actresses, and a large number of well endowed men that will never display their penises on camera.