why windows10 is last version from microsoft?

Microsoft will not launch any version after windows 10.this version will be last from microsoft. Because this is last from microsoft this is gonna be very special. Regular updates- microsoft will launch new updates instead of launching new version. User can choose between slow roleout or fast roleut. In slow roleout you will get updates in bundles and in fast roleout you will get updates just after release. Windows 10 will release in summer for pc and for smartphone it will be available in december. Please comment your opinion below about windows 10