Comment by pjmlp
CP/M was also created by one person.
CP/M was also created by one person.
In all probability, yes. I'm not sure how much easier it would be to develop though. Back then, most (if not all) of the operating system was developed in assembly language while there was far more to consider when it came down to performance and memory usage (which is often in conflict with each other). CP/M was also notorious for running on hardware that was incompatible with each other, relying upon the BIOS to smooth out those irregularities. While that may simplify the development in some respects, such as the hardware vendor developing hardware drivers, it complicates development in other respects, since CP/M development could not make assumptions about the underlying hardware.
Nice then. OTOH, CP/M 2.2 has been open sourced, but I think there are no libre assemblers for it.
Cross-assemblers, there's one: http://john.ccac.rwth-aachen.de:8000/as/ but it's tedious to build under OpenBSD.
As for software, the ZMachine and V3 games don't count as 'libre examples'.
CP/M was far more simpler.