Many already wrote it, but if all console producers stopped making them, there would suddenly be a large market for hassle-free gaming PC built and configured in ways similar to SteamBoxes. Steam configs would probably become the market leaders, having been Valve the first to take such projects so far, but there would be plenty of space for others, and Valve itself is more than glad of giving its SteamOS and providing guideline SteamBox specs to anybody asking for them.