In my experience talking to people who present themselves as knowledgable about these sorts of things, it's a self-reinforcing feedback loop. Auto makers sell

In my experience talking to people who present themselves as knowledgable about these sorts of things, it's a self-reinforcing feedback loop. Auto makers sell mostly black and white vehicles, and because of that, they think that's what people want. The reason, though, is that fleet buyers (especially governments at all levels) only buy black or white vehicles, because they're easy to brand. Ten people buying red cars with green stripes aren't going to register when the city Public Works department buys 1,000 plain white ones. Then the auto makers stop making red cars with green stripes, and the regular people end up buying black and white because that's what's available.