Valve is a "hit business" meaning that they need to produce hits to be profitable. In the short run they have been successful, but over the long run, they may run in to problems and if it does, this business model will look foolish (rightly or wrongly).
The reason, I and others on HN don't like BigCo, is because we feel stifled, but that doesn't mean that it isn't the most efficient business model.