The reality is we are going there because Google (along with Apple) are both developing 'connected tv's (aka, wifi enabled, OS running tv's). Not exactly an attempt to go right at Sony, Nintendo, etc, but Apple has shown how disruptive a sideways entry into a new market can be (or was that more of a happy accident stumble sideways?). Plus, I think the 'game companies' fail to recognize what a huge market casual games are and for most people, that's plenty enough to keep them happy.
That seems like the sort of market that google is going to win. Apple is going to want to sell you an Apple-branded piece of hardware (either a TV or a box) that lets your TV do new things. Google will simply license their technology to Samsung, LG, Panasonic and all the other existing TV manufacturers and have it built in to every TV that gets shipped.
(Except maybe Sony, who will probably attempt to build their own system. It won't work very well outside Japan.)
Let's not go there ok ?