when you look at the consumption habits of non-gay/lesbian readers, women are far more likely to be interested in reading male-male romances and men tend to be interested only in female-female pornography (not romance).

Very true. I've started reading m/m romances, some good, most sort of meh, and have found that a lot more women who've never even heard of slash or fandom like such books than I'd realized. Very interesting.

Speaking of f/f romances, I assume you've read Sarah Waters? I adored Fingersmith even though Tipping the Velvet is also very good -