This site is early proof that that idea may not be accurate. It allows you to stream relatively recent games to your PC, Mac, TV or iPad (with iPhone support coming soon), fullscreen, with pretty good detail and frame rates. I downloaded the free client and experimented some and I have to say it works much better than I had expected. You get pretty high resolution streaming gaming content, which reacts to your input without much lag. It's not quite the experience that a high-power computer delivers, but given a fast internet connection, it's dangerously close. If you're a gamer, it's worth checking out. $10 / month for access to a growing list of games (currently at over 100) isn't a bad deal.
I'm talking about the Spotification of games! As a concept, I think it's pretty cool.
Of course, this doesn't address the problem of international laws and cross-boarder data transfers, but the "performance" argument seems to be breaking down.
In the future, as more and more high-performance applications move to the cloud I can imagine the concept of Chrome Books catching on more dramatically, even as home PCs. Alternately, the holy grail idea of having the same desktop experience on any computer worldwide could actually be realized (here's hoping).