Are there any other examples that come even close?
Of course, that's all mostly because much of that was bundled with the original MSDOS.
Also, in terms of video games, a great deal of innovative techniques and games game from John D. Carmac, which of course also is a result from Id Software pushing it.
Bazaar and mercurial got created the same year as git. Before that it made you happy if people were using subversion instead of CVS.
Sure, if nobody knows about the project nobody will use it, but I think git stands on its own. If any medium project adopted it (and it seems likely that its author would be working on some other things too), I think it would spread.
Linux in particular started because a student made a task scheduler on his home computer with no real goal to make a Unixlike kernel, and it grew into it and it so happened that at the time there was a big vacuum for a free Unixlike kernel. kFreeBSD and kMinix were not yet free at that time, had they been, Linux would have no doubt stayed a hobby project.
That's not that amazing at all, because the fame and weight of being the creator of the former led to the adoption of the other as it became the official version control management system on which Linux was developed. — These are not two independent results.
If someone completely unknown developed Git 0.01 in 10 days, it would probably have stayed relatively obscure, and the reason for it's quality is because it became so famous due to being tied with Linux, attracting many developers.