Steam is fantastic, but it's a name that is totally unknown to almost all console gamers. Just the presence of a Steam Box isn't going to magically convert people, they have a huge uphill struggle ahead of them. Most of their market, IMO, is PC gamers.
Steam has a large, loyal following and, because of this, people like myself (console gamer) and my girlfriend (not a gamer) know about it through online media. I currently play PS3 games because there is no PC gaming solution I can plop down in my living room and have it just work. But once the Steam Box comes out that will change. Not only will I have a living room compatible ready-to-wear PC gaming solution, but gaming will also be cheaper because Steam has tons of deals. Steam is also reputedly a lot more developer friendly than Sony and Microsoft so I really don't see how Sony and Microsoft are going to be able to compete in the long term.
Steam is fantastic, but it's a name that is totally unknown to almost all console gamers. Just the presence of a Steam Box isn't going to magically convert people, they have a huge uphill struggle ahead of them. Most of their market, IMO, is PC gamers.