Kate,

The reason that porn movies sell so few copies is because porn is a niche product. There are thousands of different niches like bj, foot fetish, straight sex, anal etc including bi m/m, each catering to their small market.

The marketing/distribution budgets of porn studios are also tiny, even the biggest player in porn is a minnow compared to the likes of universal / disney / news corp. The other reason that the sales per title are low though is competition from the 'net. It's a medium which is more suited to delivery of adult content than dvd/vid, due to discretion, breadth of available titles and price (often free).

None of these have anything to do with your claim.

Most people buy porn for a very simple reason - to watch it and get off. They probably aren't that bothered about production values, and certainly not about homophobia. If you put something that turns them off in it, they wont buy it. So nobody with any commercial sense is going to do as you suggest. If you were correct, surely existing bi titles would be more popular than they already are?