Version control dates back to the 60s and early 70s. Not really the last decades, but literally the infancy of modern computing
Sure, and so did helpful websites are quite old as well, but nothing is quite as prolific and consolidated as stackoverflow and github. The metric seems to be about subjective relevance not originality.
if anything owes its success to being flavor of the month, it's git. mercurial was probably a better dvcs in the end, and svn wasn't all that bad before both of them. and as impactful as github has been, we had svn-based online open-source communities before git too. git/github was just there at the right time/place imo.