This type of shit happens if you intentionally mess up your own system (or use Manjaro). pacman requires extra confirmation (instructions only found in its man page) before even allowing you to delete bash (base requires it). bash has also never been replaced, and even if you deleted it, it would still be loaded in RAM. Even still, if you deleted it and immediately rebooted, it would be a quick fix for anyone familiar with the distribution they're using, and would not require reinstalling the whole thing.