In the wake of the reader announcement, I didn't even know that Google was killing the CalDAV interface for it's calendar application. That is, until I saw this article on ZDNet. I see that as more of an issue than Reader; as much as I used Reader to aggregate news, I use my calendar at work, at home, everywhere... but never in Google calendar. And I doubt that the software that I'm using is supporting the proprietary Google interface if they had the choice to use something that worked with all of the other major calendars.
I'd quit Google... but even my job is using it, making it easier to interact with it if I keep it.