I dont think its more that "program owners not realizing there are many other underserved gay niches out there", but more personal preference on the program owners part. I have never been able to enjoy a good condom video, so why would I produce something I dont care for? If your going to spend alot of time on a project, you have to enjoy it!

I think the same applys to all the niches you menchond. In the future, I would like to expand into transexual, straight, and bisexual, but need to get my foot in the door first.