No, that's not what I'm saying. If you don't separate /bin and /usr, and /usr is a mount and it becomes unresponsive, how do you log into the machine? Where a

No, that's not what I'm saying. If you don't separate /bin and /usr, and /usr is a mount and it becomes unresponsive, how do you log into the machine? Where are the login shells and basic file management tools to rescue the machine? That problem exists as soon as you collect tools into one place, whether you choose /bin or /usr/bin to be that place. But choosing (only) /bin has an additional problem, which is that you lose the ability to easily set up mounts. If you have many machines to keep in sync, they could each have a relatively simple /usr mount; while you could set up root paths equivalently, you would need more of them: either symlinks or mounts in several places on all machines that all have to be kept in sync. That is unnecessarily complicated. The /bin option is only equivalent if you are in fact dumping everything on the local disk and not using mounts. But "standard" hierarchy paths should not assume the architecture.