> Unpredictable command times. I never know if running brew install or brew upgrade is going to take 5 seconds or 20 minutes. This usually means knowing if a program or dependency is being downloaded as a prebuilt binary or compiled on the spot.

Wait, does Nix solve this? And how? The author never mentions how Nix does.

I've never encountered a package manager with this capability, so just curious how such a "global progress bar" even gets implemented.