Google has a lot of faith in their Chrome OS. So much, in fact, that they won't be satisfied with anything less than creating a paradigm shift in computer use.
In an interview with SearchEngineLand, Chrome OS product manager Caesar Sengupta went on record in an interview, stating the following:
Do you really see these types of machines taking over from the Windows computers and Macs that many people use now?
I think it depends on the user and the user's behavior. In the long term and the fullness of time, absolutely. I think we will have failed if this doesn't become your default way of computing. But right now, we see hundreds of millions of users who live on the web. For many of these users, this will replace their machines immediately, especially as web apps get better.