I agree with you. Unfettered availability of all genres is the only way to ensure that such variety exists;
As I pointed out above, when there is an intrinsic bias by an industry or PR group, it distorts the public view of the good.
Contrived example: What if the only things you could buy in blue were ladies clothing items? No, your blue jeans are not on the shelves. You have black jeans, or some other color instead. Your favorite color is blue. You REALLY wish you could get a nice navy blue T-shirt, but you cant. You can only get navy blue blouses, Dresses, etc.
Eventually, the public conciousness may come to conclude that blue is a lady's color, since all blue items are lady's clothing. The reason for this is entirely because the clothing makers have engineered it to be so-- but that's not important. The public concensus on the matter has formed, and the market has been manipulated.
The same thing happens with media. When things are allowed to just succeed or fail based on their own merits, and not because of concerted media manipulaition by PR firms, backroom deals, and the like, then things that society considers unfavorable will end up on dusty, disused shelves. It self-regulates.
If people find depictions of your female protagonist as being tasteless, vapid, flat, and genuinely unappealing-- they wont buy your game.
When they have the choice between your game, (with the vapid, hollow, and unappealing female protagonist) and some other genre that they despise even more, they will buy your game, and buy lots of it.
It is this latter effect that game publishers bank on.
Take for instance, the backlash of Kane and Lynch-- The PR drones pushed out paid for editorials, game reviews, and the like that spun the game in a direction completely different from what the game actually was-- and actively sued game review companies that voiced their true opinions. The consequence? A game that wasnt what people thought it was, sold millions of units early on. A big win for the publisher.
Then you have the "All blue clothes are women's clothing" issue. Some years are "Years of RTS", and others are "Years of online multiplay FPS". In those years, ALL of the publishers will produce very similar games, as they all try to copy each other--- leaving other genres out in the cold. Some of these trends persist for several years later, especially when there are "Lucrative franchises" to milk.
Publishers are after one thing, and one thing only--- The consumer's money.
THe consumer, on the other hand, is after a very varied and discerning buffet of items.
The publisher has interest in giving the consumer a McDonald's menu. This greatly upsets the problem, since big publishers use their financial might to kill off and prevent upstart publishers and game houses with genuinely new and invigorating content.