Watch and see.
Google OS is going to bring Linux based stuff more to the general area, and Windows + mac will slowly decrease in numbers as the Google OS is getting better and better!
Don't forget what they are doing:
3D Web applications that work smoother than others and with this OS it will be the first new generation web browser stuff OS thingy, which might get very interesting and will pull Google slowly to the top as they will be the first Next-Gen OS.
When google releases something, you should see it was an really early beta stage. In 1 year, it's more a pretty stable something. After 2 years, you can pretty much use it already. In 4-5 years, It will be stable
Google takes time and with this approach they will win the market!