I get that, but I don't really see how this is going to succeed to the point where everyone is using a steambox, rather than a normal console.
It doesn't necessarily have to cannibalize their own users and directly compete with consoles to succeed, it has a lot of crossover market appeal. The greedy comment is really silly, all products are designed to make money. It's how they go about doing it that matters and that remains to be seen in this case. Valve has a pretty good history of consumer value and customer friendly decisions so I'm not worried.
Yup. It isn't about making everyone use a Steambox, it's about getting people that prefer consoles to start using Steam. Those already using Steam on their desktop/laptop will still do that and Valve will still happily serve them and take their money.
There's a certain paranoia I keep seeing where certain people think everything is designed to screw them over or make a change they don't like and don't want. Some things are aimed at people that simply aren't you. There's a direct correlation between these people and ones that use things like "kiddie gamers" to talk about console gamers. These people are incredibly quick to talk about how different they are from other gamers yet don't think Valve is smart enough to realize this, too.
Valve isn't envisioning a world where everyone uses the Steambox. Valve is just envisioning a world where every gamer uses Steam.