> rush to get the next version of macOS out of the door

That’s the key I think. Apple these days never releases when products are ready, but on a predefined schedule. Point releases that should fix things, are actually delivering more features that were shown on the keynote, but didn’t quite make the main release date.

As a result the systems accumulated some bugs that might never get fixed, unless the code happens to be completely rewritten. The desktop switching animation is hopelessly long when using keyboard shortcuts with ProMotion enabled. On both iOS and macOS the Music app will have an audible click couple of seconds into the first played song when using lossless quality. Stuff like these is known and reported, there’s just seemingly zero bandwidth to handle it.