Too bad they turned off the Netflix side of the offer so fast. That's longer a driving incentive to get a Chromecast.
Personally, I'd prefer to have less stuff built into things.
Every "home theater" receiver you can buy today does HDMI switching. All the new ones have graphical overlays as well for things like volume controls and they have varying degrees of fancy graphical help with system setup. Once you get beyond the bottom-of-the-barrel, they've all got a variety of Internet streaming features as well (Pandora, Netflix, etc.). It seems that GoogleTV support would be the next logical step for them. The extra compute necessary to support GTV isn't going to appreciably impact the bottom-line cost of receivers above $1000, and probably not even above $500. And I guess that Google is licensing the software for free. Maybe the receiver vendors are scared of patent issues. Maybe they just move at a glacial engineering pace. I don't know.