Fiend, they may be working more, but they may be doing a different type of porn genre than Monica is after. Monica is mostly interested in doing features or high end gonzo. (Ignore that Dave Pounder scene; she was new and didn't know better.) There are a lot of factors that weigh into how many scenes someone gets.
_________________________
"What I do know is that if Karen Carpenter and Mama Cass Elliot had shared that sandwich they'd both be alive today." -Michael K