Yeah, you missed the point, I think. There's a reason I said "in general" more than once. Are you going to honestly tell me someone is going to use one of these boxes in their living room with no mouse/keyboard at all and not feel like the experience is somehow crippled? I don't buy it.
Yes, Steam has 50M users, and they'll continue to have those users, with maybe 2% of them using a Steam Box in the living room.