Or the whole chain of work culture is bad and people do not have adequate down time or brain juice to pursue these. Additionally, how many do you want to learn? I have dealt with Makefile, then recently someone decided to introduce taskfile and then someone else wanted to use build.please and someone tried to rewrite a lot of CI pipelines using python because shell scripting is too arcane, while someone decided that CI were super slow and must be hosted on premises using their favorite system(was it now drone or whatever I forgot). Eventually, things become so many and chaotic, your brain learns to copy-paste what works and hope for the best as the tool you have spent time learning will be replaced in few months.
And... again, I have to say that that kind of statement is absolutely of a piece with the analysis upthread. Someone who demands a "work culture" that provides "down time" or "brain juice" to learn to write a makefile... just isn't going to learn to write a makefile.
I mean, I didn't learn make during "downtime". I learned it by hacking on stuff for fun. And honed the skills later on after having written some really terrible build integration for my first/second/whatever job: a task I ended up doing because I had already learned make.
It all feeds back. Skills are the components you use to make a career, it doesn't work if you expect to get the skills like compensation.
In an ideal world build tools would just work and people wouldn't have to think about them at all.