yeah, but first off pedagogy isn't the same as praxis. also, (western) math has moved from its Euclidean geometric roots to much more efficient and powerful representations. that is to say, i'm not convinced that low-level memory management is actually a fundamental skill.
anyway, people can and do learn these things if and when necessary; what's happening is that there are so many other things to do now (this is called progress) that people don't have to do them. further, the people who actually do these things are benefitting from modern approaches. even demo writers using decades-old hardware are making graphics which would have been considered jaw-droppingly impossible at the time.