Disclaimer: I haven't programmed on Windows in a very long time, and the only time I did it was in a cocoon of an intro programming class in VS.NET where we didn't have to program anything that was either useful or interesting.
However, one of the more substantive complaints about Windows I've heard (beyond the usual instability and insecurity) is that it isn't easily programmable. You can't (I've read) effortlessly connect small, well-designed, single-purpose programs together with things like pipes, redirection, etc. And, most programs by default (again, I've read) are inextricably attached to their GUIs, so you can't make them scriptable like you can with a command-line Unix tool plus a shell script. That would mightily suck for anyone who's used to the high level of programmability in Unix.
1. Why would they quit?
2. Why is this funny?
XP is stable. It loads executables, runs them, moves files around etc, without much fuss. Google's code runs mostly on interpreters, so...wtf? The only people who should care are the accountants who would have to pay Microsoft. I mean: Is the punchline, "Ha, ha, google's engineers really are as immature as the bean bag chairs suggest"?
(I withdraw my question if the answer is, "Because they wouldn't want to spend months on useless administrative tasks like re-installing OSes.")