Any company could ostensibly enter the market, assuming they had a disruptive enough product. Certainly few companies could compete in the brute-force manner that Sony and Microsoft rely on, but it didn't take much capital overall for Nintendo to get the Wii off the ground, and look at what it's done.
As for how likely it is, I'd say not very. At this point, you'd have to invent something even more intuitive, focused, and user-friendly than the Wii, and that's a tough order to fill. And to make it even more difficult, marketing divisions of companies tend to shoot down disruptive ideas as "never going to work". Which is terribly ironic since truly disruptive products have an obscenely high rate of success.
Sky Render - Sanity is for the weak.
