But notice the graph is comparing IE9, which won't be out for two more years, against currently shipping browsers. Since it's still dead last in all those categories today, and the other browsers are moving ahead of that, just how bad is IE9 going to be when it comes out? At the rate they're going, no one may care cause no one will be using it. Especially now that ChromeOS will be out in a few months.
ChromeOS looks fairly weak feature wise, though I'll reserve my full judgement until I actually try it. It will probably make a good dual boot option for my netbook when I just want to surf & listen to music, it's *meant* to be a lot lighter and quicker on power-lacking systems. I don't see it as a threat to IE9 or windows in general (at least right now), it doesn't have enough to replace it.
The one pitfall I see is that if everything is in the cloud, without internet (say in the car on highway, in and out of signal; on a plane) it would become useless.
The idea of a portable notebook is to take it places, if I'm restricted to my home, it's not very handy. We don't have wifi everywhere like some cities do.