I never had a Mac in the 90s/early 2000s, but a lot of this still sounds pretty familiar as a passionate Palm OS user at the time:

No memory protection, no multitasking (not even threads!), more minimalistic than the competition at the time in many ways in its core features – but on the flip side, extremely extensible in almost every way.

As I later learned, PalmOS was heavily inspired by Mac OS!