I think they would release Half Life 3 and other games as "Steam Box 1 Minimum" which is to say, you either buy the box or your computer must meet the minimum conditions of the dedicated box. Valve is devoted to creating an experience, and it's sad that consoles are such a limiting factor in game development, even though it makes sense.

I guess this is their midstep until OnLive-esque cloud gaming is more dependable/available.