If Microsoft does in fact make this a deadline and does start charging for an operating system they have basically given away for the past few years it would most certainly put a nail in the coffin. Especially with Chromebook becoming such a player/threat to their existence. Even Apple is feeling the pinch of the Chromebook. It should be an interesting Summer, should this actually take place!
http://thenextweb.com/microsoft/2016/05/05/millions-microsoft-users-going-miss-free-windows-10-upgrade/