Earlier quoted context omitted.
Yeah they wouldn't just toss away millions of lines of kernel code.
They've done it before, when they replaced the foundation under DOS/Win3/Win95/Win98/WinMe line with WinNT, and Apple did it when they replaced the foundation under MacOS 1-9 with NextStep and called in OS X. Apple's non-unix line endings (CR) changed to LF, their non-unix path delimiter (:) changed to /, and they were suddenly a major force among non-Apple-targeting developers who had always derided the Mac as a "to…
That was because with OS X, they switched from a Mac OS subsystem to a Unix subsystem