> Microsoft has started hiring Linux kernel developers like Matthew
> Wilcox, Paul Shilovsky, and (in mid-2016) Stephen Hemminger...
> Microsoft now employs 12 Linux kernel contributors.

Hiring kernel developers sounds like business-as-usual for Microsoft. Go back to 1988 when Microsoft were in need a new kernel to replace DOS - OS/2. From Wikipedia...

"Microsoft hired a group of developers from Digital Equipment Corporation led by Dave Cutler to build Windows NT, and many elements of the design reflect earlier DEC experience with Cutler's VMS and RSX-11, but also an unreleased object-based operating system developed by Dave Cutler for DEC Prism."

cheers,
Ian.