How did Disk Utility.app go from being one of the great built-in OS X utilities to the embarrassing amateurish shit show that it is today? Perhaps the same people responsible for the file system engineering are also responsible for developing this user-facing application. They might excel at low level system engineering, but they are utterly unqualified to develop a high level GUI application. Spend 5 minutes with th…
There have been a few cases like this. Presumably the original was created/maintained by just one person, they move on, and then when the next person comes along they decide it's easier to re-write than modify the old code. But they don't have sufficient time and the new version is inferior to the old. Bear in mind the old version did need to be updated (new CoreStorage features, has to handle Fusion drives, now APFS…
(this is 75% speculation on my part and 25% confirmed by conversations with 2 ex-apple engineers.)