One factor is that most people who want to play games with the PS mostly can get them for cheap and own a console to play it on....most. People who want to play a PS game on a Dreamcast nowadays like me are rare. My son and I love playing the Spider-Man 2: Enter Electro game via Bleemcast. That iso does exist btw - so you do not have to do the swap disc thing.
I only wish "Wheel of Fortune" or "Who Wants To Be A Millionaire" (US, not UK) was "bleemed". Those games may not be possible. To note, there is a UK version on Dreamcast of "Who Wants To Be A Millionaire".