> Also, the optimism just highlighted how out of touch they were, that they thought people would actually just rewrite everything in 5 years is bizarre and suggests a fundamental lack of understanding to me. Same thing with Wayland and GPLv3 to me.

It is the fundamental difference in the developer's origin/experience in FOSS projects vs commercial software. However, there is an even bigger paradigm difference underneath. Academia survives on one-off projects and FOSS is often recruits students in universities who contribute as hobby, without contracts. The usual POSIX software is all about exposing things with minimal abstractions. It makes developing and iterating on software easier on the developer.

People who work in commercial software are forced into decade-long support contracts. So they develop skills in managing long-term backwards compatibility. This comes with the abstractions and software designs with more thought into their future.

You see that in Windows components that the engineers thought about how the computer systems will evolve and allocated some slack to extend the software: https://faultlore.com/blah/c-isnt-a-language/#case-study-min... . This kind of hindsight isn't something one can easily learn without being forced into the backwards compatibility and getting burned before or mentored. Some of the skills also means that you need to learn where to place the "narrow waist" of the API.

To illustrate the difference I'll actually compare Win32 vs X11/Wayland. Win32 is a much better abstraction and much better "narrow waist" point than X11 was. X11 was designed tightly around 80's hardware and people had to add hacks on top of hacks to actually make things like GPUs work. X11's network transparent architecture actually made implementing direct rendering harder. While Win32 already had some ideas that made into Wayland and it designed nice abstractions for allocating windows, direct rendering buffers and compositing. Win32 had baked in concepts like a window or a button or text rendering. So when the devices with HighDPI appeared or when new security boundaries needed the higher level abstractions of Win32 made it possible for Microsoft to make smaller API changes while the whole X11 started to collapse with 90s hardware and then was useless for 2010s.