the games-sales market is actually half (or-less. Really, there's a distinct possible-reality where the under-served market mirrors virtually every other media market (but explicitly film, books, TV) where women significantly outpace men as consumers of narrative and fiction.) of what some market trends suggest it should be because they only engage half (or less) the audience they could.
There's a huge niche opening for game design and game publishing to appeal to that other half-audience which is going completely unfulfilled.
Ask yourself, why does the explicit portion of women that make up the dominant share of the book-buying market make up a negligible share of the gaming market? (That is, why do the very-same women that buy/read fiction not generally buy/play video-games as a form of interactive fiction? It's like a 90/10% split; 90% of women who buy/read non-genre fiction do not play games.) It's certainly not because women are less savvy then men and we know factually they're much larger consumers of narrative-media product. It's because nobody is producing product for them.