The easiest way to convince management to invest Time in a SCCS is focus on backup and archival. By utilizing something like Subversion (SVN), you can restore any project to any point in time instantly. There is no need to have someone look through backup tapes or worry about tracking multiple versions in an obtuse directory structure.
There are obviously many other advantages (i.e. 2 people working on the same file at the same time), but backups are what quickly sold my company many years ago.
