While Microsoft might have lost the server battle, those of us deploying on Azure hardly bother with which OS the type 1 hypervisors are actually running, many Azure workloads could even running directly on the hypervisors that we wouldn't really notice.

As for the desktop, regardless of all screw ups since Windows 8, GNU/Linux has hardly made any gain there.

Then we can turn into mobile space, which they did lose, however in what concerns tablets, hybrid laptops running Windows win out clusmy Android tablets every day of the week.

Finally, WSL is there to cater to the same folks that buy Macs to develop Linux instead of supporting Linux OEMs.

Who knows, maybe Apple will upgrade sandboxing to jails/containers and add a FreeBSD-style Linux compatibility layer. Or maybe they'll go full-on MS and include a Linux kernel alongside Xnu using Hypervisor.framework. (Note that in my experience the networking design of Ubuntu on WSL broke containers that worked fine on regular Ubuntu in Virtualbox/VMware/etc., but YMMV.)

Something like that is certainly possible, though they'd have to have some reason for it, and they don't appear to at the moment.