When I was a student, the old "the university is not a school" culture was still strong in my university. The idea was that universities were places of learning, not teaching. Formal teaching was a supporting activity rather than a core part of education. The university made a honest effort to support you to the extent its resources allowed, but the responsibility to learn was 100% yours. If you failed a mandatory exam because the university could not offer the corresponding class that year, it was your fault.
While we are bringing up this point, it doesn't have to be quantum mechanics. The invention of algebra based physics classes (which is Mechanics and EM) without calculus is the same thing. Instructors mostly are teaching trust me these are the formulas to use them and this how to use them.
That's an extraordinary rise in grades. It seems like part of the conscientious discharge of your job would be to compile the evidence that these instructors did _not_.
As an administrator for an Extension school (at a major university), I inherited a set of Accounting instructors who failed most of their students in intro courses, and took pride in doing so! In their view, they bore no responsibility for their students' success, or lack thereof. The students needed to work harder.
I replaced all of them with instructors (men and women) who had much better professional credentials ... whose students earned mostly A's and B's. There's no evidence that the second set of instructors lowered the standard in any way - their students continued to do well in the program. The new instructors just taught better, and cared more.
Unless admissions massively screwed up and people who can't do algebra are suddenly taking quantum physics, it's almost always the instructor's fault. But being an instructor (in US HCOL areas) is such a poorly paid and ill-respected profession, it often doesn't attract the best and brightest.