> it's also interesting they have completely separate windows and mac code bases.

At the time I don’t really think that was uncommon.

I mean, you barely had FOSS portable libraries to base the core functionality on, even before you started tackling platform specific issues.

There were different CPU architectures. Machines back then were completely different, with each type having it’s separate types of HW devices and connectors. Etc etc.

Literally nothing were common between PCs and Macs. I’m not surprised at all.