Valve has stated they want to bring the community closer together for buying/selling/trading of goods. I would expect they would make their money that way.

I doubt they would dump DirectX completely. They've reworked the engine for linux to not care if it's running DirectX or OpenGL. Leaving this intact could provide a way to eventually port to Android/iOS and other mobile platforms? Valve has stated they want to get into the mobile space but have seemed to fail thus far. I recall them mentioning Linux was a natural step to go from Win Desktop -> Mac -> Linux to Mobile running Linux (Android)