Hmm. Seemed like a good idea at the time.
I can’t recall the details, but apparently I was having backups fail because something changed while the backup was happening. The only way that I can think of for files to change during a backup is for something to get moved to tombstone, or a file is being uploaded when tar starts?
I suspect that another solution (other than for luck during a backup) is to turn on read only during backup.
Having to install homebrew to make development work on the Mac does seem onerous. I have been using the gnu utilities for decades, so I didn’t think about them not being available on the Mac.
I guess the simple thing is to revert my change. Or we could test which version of tar is available.