Xbox is designed for kids, who's parents don't want them to have full access to a desktop computer and don't know how powerful of a gaming computer they need (people like to claim its cheaper but it really isn't, and it's easier to spend more on fast hardware you don't really need).

Because of this eco-system for kids, xbox has great multiplayer support (including locally for friends), and the software was a clearer focus with less bloat. I don't see xbox market going away any time soon unless people stop having kids