They will adapt.

Embrace, extend, extinguish. They will become Linux.

In all seriousness, if you look into how windows manages its security now, it leverages virtualization to essentially run windows inside of a hypervisor. At some point in the future, the legacy windows kernel is going to just be another virtual machine running side by side with Linux and the hypervisor will probably run their HyperV tech on top of a Linux (compatible) kernel.

Then they will say that you need their version of Linux to run specific hardware and software.

EEE