Innovation and advance are impossible without change, and implementing change successfully is crucial to Apple. Here are two examples of it not going right.
Classic resource forks passed into Mac OS X, but were deprecated by Apple in 10.8. Now in Catalina they can stop working: is this a new security measure?
When everything is running sweetly, macOS performance isn’t a problem. In most respects, though, 10.15 is no better prepared to cope with problems than 10.0 was almost 20 years ago.
Many files in macOS are more than just their data, and contain metadata in extended attributes. Does macOS know the true size of any file, taking into account those attributes?
A traditional ‘resource fork’ containing resource structures, lumped into a binary xattr. Still commonly used for image previews, and found in many older files.