RCS was okay if you were a sysadmin, terrible for everyone else. CVS was okay, but still limited. SVN was more advanced, but buggy as hell. Git is more advanced and less buggy, but over-complicated and unintuitive.

Git was actually started in order to complete core functionality and let someone else make the front-end for the VCS. But somewhere along the line people just decided they didn't need a user friendly frontend, and now the core is what people use every day. 13 years later and it's still difficult to use. Unless someone comes up with a really slick universal frontend for it, it's probably time for a new VCS.