I feel you on this. Having done a lot of Python consulting for engineers and scientists, it is absolutely the case that most non-programmers have -zero- model of what I/O latency and bandwidth limitations look like. They are looking at programming APIs, and their mental models can include concepts like files and even byte layouts within files. But they generally have no working model of how a physical computer actually implements those things.

I've definitely seen file I/O in the middle of FORTRAN loops. Entirely correct from a functional perspective, and total disaster from an actual runtime perspective.