Microsoft Windows 10 is no longer just an OS it is now a service, just like the new Office 365. Microsoft charges their customers monthly or yearly to use office 365 also known as the "service". I have a hunch that it won't be long before Microsoft will charge customers to use Windows as well.
I switched to Linux almost immediately after the release of Windows 10 and would never go back. Something tells me if Microsoft starts to charge for Windows then Linux will become very, very, popular.