Is it really the same? Or more like `rm -rf /usr` ? Was this folder always required to maintain the integrity of the system, or is this a more recent thing?
It's actually quite similar; it used to be that all the "system" binaries were in /bin and /sbin and the "other stuff" was in /usr/bin and /usr/sbin but that has not been true for quite a while on many distributions.
"back in the time", /usr could be on a network drive, and /bin had to contain just enough stuff to boot the system, set up networking and mount the /usr
Interestingly I actually did manage to make my /usr partition unmountable a few years ago on a system where I had changed the shell for the root user from /bin/sh to /usr/local/bin/bash and ever since then I have kept the default shell for the root user on my systems unmodified :)
Back in PDP-11 days (Unix v.6) my boss managed to do a "rm -fr *" not in his personal bin (as he believed ATM) but in the system bin. Oooooops. (but Armando S was ready with functioning backups.)
I've been in a similar state - I had a shell running but lost /bin/ls among other things; but I could use "echo *" and redirection to recreate an /etc/mtab.
On most Linux distributions, it's basically the same. Your package manager tends to make no distinction between OS files and installed program files.
FreeBSD does another approach, where user-installed packages go to /usr/local and don't get intermixed with the base operating system.
rm -rf /*bin/* would probably be more similar to deleting "program files"