To me what was most surprising about Dwarf Fortress, given the complexity, is that Tad didn’t use git or any other code repository until more recently.
Well, if you deeply understand the code and reasons behind it (or it's superbly documented esp. with tests), the tool does not bring much beyond being a convenient backup or checkpoint system. And especially if you don't have to work with a team.
Is it possible to climb a mountain without equipment? Sure, but it's a lot more dangerous and it'll take you longer to reach your goal.