They want to move everyone to Windows 10. This does not involve shutting down support for anything else. The support periods are published a long time ahead, and as you say yourself, Windows 7 will be supported until 2020.
> Win10 is not going to be installed in any business that needs high data security either for operations or regulatory requirements like HIPPA or the SEC, etc.
You appear to have missed the fact that the US Defense Department has already starting moving four million users to Windows 10 precisely because of the advanced security. I know banks and other organizations that are moving, too.
DoD-Wide Windows 10 Rapid Deployment to Boost Cybersecurity By Cheryl Pellerin DoD News, Defense Media Activity http://www.defense.gov/-News-Article-View/Article/688721/dod...