You are either missing my point or willfully ignoring it. My point is that if those engineers who didn’t get it are still gainfully employed, and meanwhile the ones who did get it are employed in jobs that do need all of those more difficult topics, then why should we dumb down the curriculum?
We shouldn’t be lowering the bar. Students who excel at those topics can often grab jobs that require them (if they so choose). Students who struggle with them can still go get jobs that don’t require them anyway. If we removed those topics, those top students would be at a substantial disadvantage compared to now, and nobody wins.