There exist purely theoretical computer science topics. Ullman's automata theory lectures are freely (legally?) available online. There are also authors like

There exist purely theoretical computer science topics. Ullman's automata theory lectures are freely (legally?) available online. There are also authors like Knuth who are surprisingly practical. This problem goes way beyond math and programming and into physics and general engineering. There are a surprising number of engineers who can manipulate the linear algebra tools but can't actually engineer structures or figure out linear circuits. EE filter design is another good example. If you look at higher ed vocational training as kind of a prep-school or maybe a qualification filter for an apprenticeship it makes more sense. Once you figure out linear algebra you're qualified to apprentice to someone to teach you how to actually use it.