Microsoft made the switch from DOS-based with Windows as a layer to full Windows-based ("NT") operating systems by having both for several years. They could pro

Microsoft made the switch from DOS-based with Windows as a layer to full Windows-based ("NT") operating systems by having both for several years. They could probably offer a Linux kernel with whatever Windows OS services mattered most for the future in parallel with regular Windows for a decade or so. Doing so might give them a more attractive offering for the future while retaining most of the Windows legacy business. It would also let them leave lots of legacy problems behind, and pick up a lot of the "real desktop computer for real work" business that Apple is pushing away in its own gradual transition to the "controlled purchasing portal" OS they love.