It's like Silverlight. Initially people were like "oh flash is already on 99% of computers" but failed to realize the fact that 99% (not really, but close enough) of computers come with Windows, and Microsoft controls Windows. Microsoft, when ready, can easily get people to use it.

And with Google, all it has to do is slap that browser on its front page if it really wanted the average user to switch.

Obviously Google chrome still has some kinks, so they won't want the average user to switch just yet (assuming that's even their goal).