> Most major research uni profs are obliged to teach 2-3 courses per semester.

IME, that's a heavy courseload. At the university where I work (not as faculty), it's closer to 1 course per semester on average. Maybe 2 occasionally, but that leaves very little time for research.

Your profile says you're a mechanical engineer. At research universities, 1 course per semester is typical in engineering departments. That's definitely not the case across all departments.

I'm also an ME, but I have a masters degree in Marine Science. The professors in my graduate program usually only taught one class a semester, some only one a year. From my experience it very much depends on the university. Some schools are much more focuses on teaching and others on research.

> that's less than 10% of profs at big name research-driven schools

From my experience that extends quite a bit further than that too even for a university that wasn't research heavy. I'd argue about half of my lecturers at university back in the day saw Level 1 classes not only as a hassle, but had active disdain for teaching them.

Which is totally backwards, as these classes are the point of contact where energetic, motivated new students get that magical passion that pushes them into an entire life in the field. When I was in grad school and expressed a desire to focus on teaching, primarily 100 & 200 level courses my supervisor said "that's the punishment we reserve for those who are failing in their research". Totally crushed my desire to work at converting tangential students into future leaders in our field.