You don't need two OSes. For applications there is lots of work to make it really nice. Putting mobile apps on "desktop" can be done, while user interface will

You don't need two OSes. For applications there is lots of work to make it really nice. Putting mobile apps on "desktop" can be done, while user interface will be a bit strange. But that's a thing which needs time. Microsoft tried that by pushing mobile on desktop, but they didn't have the mobile story. Apple has notable Userbase on both.