I read it's a cabal like most things and they keep new actors out to keep getting work. like you said be real easy to just grab some cheap stunt dicks.
Lucky for them since they get to do it with hot girls that they can't score outside of work since even av idols probably wouldn't be attracted to them if they're not contracted. idk if it's a good thing for the av idols. Theyre less attractive smelly chubby old farts. Also, Some guys enjoy watching the intensity of bbc, but not even all white girls enjoy a full hard thrust either. I guess it appeal to those that think they have a chance too and boost their own self esteem. Ugly guys don't need to be ashamed about dating hot girls, but here they're getting paid too.
There's ton of niche like retirement home grandpa, the ugly household from s1, midget, and more usually portraying them as rapists. The old guy even made some headlines like Shimiken as the oldest pornstars that always get pair up with young hot milfs. He's not some lonely old guy, but have a pretty healthy family himself despite trying to keep his av job off topic.
It's definitely cheaper than flying to l.a and use those actors. They probably don't even have the budget for amwf. R18 stopped going to avn and the number of girls that went last year decreased.