Earlier quoted context omitted.
Most engineers I know have not learned set theory or groups/rings/lattices. They still seem to be doing pretty well.
From what I've observed, most engineers are glad to be done with math when they finish college. Most engineering is qualitative: Organizing and arranging things, making things fit together, and troubleshooting. Maybe 10% of engineering is quantitative, and that work often goes to the handful of people in the department who have maintained an interest in it. Some of the engineers who attract quantitative work are peop…
Depends on what you're doing. My father did a huge amount of mathematical analysis over the years (roofs, bridges, trusses, ship hulls), but, again, he had the mathematical ability to do it. One of my best friends gets called into big institutional HVAC systems when they're misbehaving, and pretty much makes his living from qualitative understanding of dynamical systems that requires this kind of foundation.