Re: To some MSDOS was an major leap forward.
Cromix from Cromenco was Z80 and then 68000 / Z80 hybrid, then 68000 only. It certainly looked like Unix.
Xenix though needed a minimum of a 286.
The Z8000 was late and a disaster compared to 68000. The 8088/8086 was really more like like an 8080/8085/Z80 than a 16 bit CPU. Clue is fact that Intel had a 8080 to 8086 Assembly translator and it used 64K pages. DOS pretty much was a clone of CP/M86, which was barely more than a translation of CP/M 80.
DOS and 8088 and IBM PC held PC back for 10 years. No wonder Acorn developed ARM & RiscOS, though the Archimedies Unix was 1987, I think, which was after 80286 (1982) and 68000 (1979!) ports of Xenix and Cromix.
Almost every 286 ran purely DOS and x86 mode. Very few had Unix / Xenix. CP/M was great in 1974, but to essentially base PC DOS/MS DOS on it and use the 8088 in 1980 (1981 UK) was madness and it was a disaster that it became popular. Still amazing that Apple II was still selling and there there were far better machines using 8088/8086 than the IBM, like the Victor 9000 / ACT Sirius 1. The PC was clunky garbage.
DOS wasn't even doing subdirectories till maybe 2.11? Only "Mature" at 3.3, DOS 4.x and 5.x Pointless. DOS 6.22 only good to load WFWG3.11. It and especially Win9x held back real Windows (NT), which MS has progressively broken since releasing Vista (Win 7, really NT 6.1 was Vista service pack).
Meanwhile Linux which was a curiosity when NT first released (came out at similar time) gradually got better and was decent enough by 1999 for servers, and Desktop by 2007. Now Linux Mint + Mate is seriously better than Win 10 (Should be Win NT 7.3 approx).
It's a mystery why IBM did what they did and Digital Research didn't sue MS out of existence. But then MS had previous with BASIC. They didn't develop it, it was a port of Dartmouth BASIC.