Game industry would be one source. At least for many teams and projects, Git isn't very useful (horrible for large binary files common in AAA games). So many companies still use Perforce or sometimes you'll see SVN still. That means a whole bunch of really qualified engineers who have never or rarely used git.
I'm sure there are other industries for which that is true too.
It's a good reminder how small a section of the tech industry comments on Hacker News.
I've encountered this myself as someone who maintains small open source games. Engineers with vastly more experience than I do have approached me with contributions, but needed me to walk them through installing and using git. You could tell they were good engineers because they were so eager and happy to learn it. I can't speak for how big of a demographic these types of engineers are but they certainly exist.
I started at the end of this era, working on a monitoring team that supported mainframes, network and data center systems. My second week on the job, my delivery of books arrived. About 30 linear feet of documentation. Iirc, it was part of our ELA.
I kept a couple of the references that I spent a lot of time in, along with my Perl books. Good times.
I'm sure there are other industries for which that is true too.
It's a good reminder how small a section of the tech industry comments on Hacker News.