[marsten]

In fairness to all concerned, the MacOS to MacOS X transition was brilliantly executed. These days we take VMs for granted, but back then it was a novel idea to run MacOS 8 as a process inside of MacOS X (the "blue box"). For most users it was seamless.

[bombcar]

Microsoft had done something similar (twice!) but Apple polished the living daylights out of it.

[LexGray]

Yet they completely failed to do so for Mac 32-bit apps. There is a huge library of apps that have not been updated to 64-bit to this day and it is a travesty they never released a virtual classic mode to run 32-bit and even OS 9 apps. It is the one place Microsoft shines in comparison, and the only excuse they give is “deal with it”.

I am certain the reason Wine never tried Mac emulators is fear of Apple legal and consequently you far more easily run ancient Windows programs on Mac then you can even fairly recent Mac Applications.

[wat10000]

32-bit apps continued to be supported for a couple of releases after 64-bit rolled out. Just like Classic.

[marsten]

I can see Apple's position: The Mac has been through four major ISAs and the value to most users of maintaining that entire stack indefinitely in the current macOS is nil.

A number of digital preservation standards are emerging (Wasm, MAME/MESS, EaaSI, Olive, ...) and I would like to see a legal requirement on OS vendors that platforms that are no longer supported must be made available to archivists.

[wat10000]

Apple did it before as well. A/UX ran System 7 in a UNIX process. That was a really niche system, though.

[bombcar]

That and XENIX are really interesting “what might have beens”.