Remember: If you're reading Hacker News, you're not a "typical computer user". You're not the type of person that's lining Google's pockets -- you're probably a cost.
Most "typical computer users" don't hate Microsoft. They're happily using Word and IE, love FreeCell, and couldn't tell you what Emacs or The Gimp were to save their lives. People stopped reflexively typing 'yahoo' and 'altavista' pretty easily when their friends recommended 'google' and could do the same for 'bing'.
Keystrokes aren't a switching cost and Google isn't nearly as invincible as you might think.