Thing is, what percentage of people are going to actually want to use a web browser on their TV downstairs? Generally, people are going to have their consoles connected to a TV in a living room or bedroom, sitting away from them. Often it's going to be an SDTV, so internet at a resolution of 854x480 will look pretty shocking. I know I wouldn't want to use it at that resolution. Even on a decent TV running 1280x720 or 1920x1080, the fonts are going to be TINY, and you'd need to be sitting right up close to the TV to actually see them on something like a 32in TV.
Internet for TV has been trying to take off for ages, just nobody seems to buy them. Sure we have the broadband era now, but for the most part, people are just going to want to stick their PC on and use it for the internet there, as you can do so much more than just browse on the PC.