"some kind of revision control" =/= rcs, and eight years is quite a while. I'd happily bet that more sysadmins know git than rcs if you find a measurement.
3-5 years ago what I saw was some CVS, some subversion. Nowadays it's some subversion, some git, maybe a bit of CVS hanging around. I had literally never heard of any sysadmins (or in fact anyone except one aging college professor) still using rcs prior to this thread.
If you've used Subversion, you've used CVS. If you've used CVS, you've used RCS. My whole point was that your average sysadmin is familiar with an RCS model, versus the Git model, which is incredibly different and a huge learning curve over older tools.
There are a lot of sysadmins out there. Most of them are older than 25, and most of them do not work in Silicon Valley. They work on all kinds of systems, for all kinds of companies. Any company that's been in operation for more than 10 years has files managed by CVS, or RCS if they've been around longer. They probably also use other tools and systems you've never heard of.
But that's OK. Today you'll get hired to manage new systems with new tools. In years to come, somebody will tell you how nobody uses SVN or Git anymore, and they've never heard of anyone that does.
That would explain it - you've probably been working with sysadmins who've been doing their job for less than 10 years. Any Unix sysadmin with more than 10 years experience knows rcs very well. You typically see subversion where there is a server involved in version control.
It's what I learned in College, saw again at Netscape, again at Loudcloud/Opsware (though, for source control of code, they used Clearcase of all things. Shudder.) - always for the purpose of managing a single file. Once there was more than one file, something else was typically used.
