Because unlike sendmail, CVS hasn't been effectively broken for even one decade, let alone two.
Also, because CVS meshes better with their development philosophy (something about the fact that everything's in one repo, and CVS allows checking out portions of a repo, whereas Git only lets you check out the whole repo).
Just because it isn't as trendy or hip as Git doesn't mean it's automatically broken or obsolete.
I've had an intensive use of CVS for years, followed by an intensive use of SVN for years.
During my CVS years, I never ran into an issue. ever. We can all agree it lacks many useful features but it's also as easy as it can get and it does not corrupt repositories. Calling it "broken" is far from truth.
During my SVN years, I can recall two repository corruptions which no matter how they occurred, just should not have. I think one was related to a bug in the db(3) backend, the other I dunno as I was not in charge of the repository. So... "superior" is debatable.
Nowadays I mostly use Git and CVS, both for different purposes and both making sense in their own purpose. I would not be so affirmative about technologies because you only know so much from your experience and use-cases ;-)
Also, because CVS meshes better with their development philosophy (something about the fact that everything's in one repo, and CVS allows checking out portions of a repo, whereas Git only lets you check out the whole repo).
Just because it isn't as trendy or hip as Git doesn't mean it's automatically broken or obsolete.