Your second paragraph is basically what I meant: The complexity is just too high. This is especially true when downloading data from the internet is involved.

Your second paragraph is basically what I meant: The complexity is just too high. This is especially true when downloading data from the internet is involved. But the first example, git housekeeping, depends only on information readily available locally. git could just give this information to any calling program that needs it, but my guess is that nobody thinks that progress bars are worth it. Actually, in today's world, I'd be happy if progress bars (or even indefinite loading indicators) would even show me when the process has crashed and won't ever finish, but they'll happily show "progress" that will never finish.