My impression is that Google wants web browsers to be better in general. When people have a fast powerful browser, they're more willing to use rich web apps, an

My impression is that Google wants web browsers to be better in general. When people have a fast powerful browser, they're more willing to use rich web apps, and they spend more time online, both of which benefit Google. The primary purpose of chrome is to drive innovation in browsers, and to mitigate the downside risk of some company controlling the whole market and shutting Google out entirely.