Comment by indymike

OS 8 was designed to run on 68020 without the mmu so you could run on the Mac II and LC. Likewise, MS was trying to keep backwards compatibility with windows 3.11 era software which led to 98 being a compromise, where NT was a much better os. Incidentally, you could pop in an MMU and install A/UX for a os 8 style ui running Unix underneath on those older Macs.