This is possibly pg's most misunderstood essay ever, largely due to reactions like this one. He didn't say Microsoft is "dying," just that they're not a threat anymore.

And ultimately, it's for their own good! Microsoft's rapaciousness was hurting them, indirectly. Innovation in the Windows space dried up. Who wants to make the next big successful thing on Windows, when Microsoft will surely swoop in and eat your lunch for you?