Some truly revolutionary things have been around in UNIX for a very long time because they're just that good. Some are around as-is: find, netstat or ifconfig for example. Others have been improved upon ad infinitum, like vim (a better, sleeker version of vi that somehow stays true to its vi roots).
I was forced to deal with cpio last week at work. It seems there are some old scripts that keep using cpio for archiving data. I found out that the version of cpio that we had running wouldn't acknowledge files owned by users or groups with a UID or GID higher than 65,535. This is the typical "32-bit UID/GID" problem that got fixed in the REST OF UNIX back in the 1990s sometime. While poking around, I found that the earliest version of cpio was actually written by a caveman named Ungh in abacus-native machine code. The dude had serious skills. Apparently, though, no one's bothered to update it in the last few millennia.
(not recommended... haha!)
Extract files from a cpio archive
And similarly, if you run across the bizarre gzipped cpio file, you can do this:
(Props to [jdoublep] for the hilarious post title)