Wasn’t the NeXT play an acknowledgement of the difficulty of writing and maintaining an OS?
The CHRP/PReP crater must have been smoking as NeXT was merged in.
NeXTStep had been ported to just about every major processor by that time (SPARC, i386, PPC, PA-RISC) and brought along a powerful platform-crossing development toolchain.
With that flexibility, it’s a wonder macOS hasn’t yet made its debut on full-blown Apple/ARM hardware.
Is it a matter of defining that future configuration? A new take on the DuoDock?