First thing: great, there are indeed too many users for whom Outlook is the email interface.
However, who doesn't Google try and improve the very poor UI of Gmail first? There's no vertical view (humans find reading short columns easier than wide lines), no message body preview, Google calendar is invisible, the whole thing seems quite ghetto when compared even to Hotmail.
I disagree. I like Gmail's email interface best, and I like that I can scan many messages quickly ---even on small screens.
But Google publishes a solution: the Google Apps API. Also, since it's email, you can simply import, forward, or sync your Google mail into any other mail application that you like better.
However, who doesn't Google try and improve the very poor UI of Gmail first? There's no vertical view (humans find reading short columns easier than wide lines), no message body preview, Google calendar is invisible, the whole thing seems quite ghetto when compared even to Hotmail.