For corporate products, it's easy to see why this would happen so often; there are a hundred tacky people with no sense of taste for every one person with a strongly developed sense of taste. The people with taste have finite political capital in their organization, and they aren't going to spend it all fighting the constant stream of tacky crap.

The only way around this is to find a tasteful design czar and invest them with a huge amount of political capital. Steve Jobs held this role when he was alive. It's rare, unfortunately, that arrangements like this emerge.