The politics of this are interesting, and IMO related to the decline of the PC as a platform. Suddenly Microsoft is the outsider crying for "openness" and "freedom" while hammering on the gates of the Google/Apple ecosystem. For Microsoft, it's less bad if everyone switches to an uncontrolled platform than if they switch to a platform locked in by a competitor. The embrace/extend/extinguish logic works the other way…
Why would this signal the death of PC? If anything this is most closely related to the death of Windows Server, since a ton of application development is done via the web.