I've had professors that did more damage by 'teaching' (I use that term loosely) than if they had just said 'learn it from the book/online and show up for labs/tests/exams'. Mostly it was because they had no idea how teaching worked.
It's a very faculty-centric view because from a student's perspective, the teaching is 99% of the school. Very few will go on to research. They come to school to learn and earn a degree. If the University cannot provide good teachers, they are not a good university. If a professor cannot teach, they are not a good professor. That isn't a moral judgement, its just the subjective judgement from the other side of the school-desk.
The distribution is one thing, but grade correlation with other statistics might be more revealing. In particular, how do you know that wealthier students aren't hiring people to take the exam for them?
The other thing I do is I don't make exams so weighty. If you ace the exam but you don't do well on the assignments, you're not getting an A in the course. So the hypothetical wealthy cheater will have to keep their body double on retainer for the semester.
But I will say that the students who earn an "A" are ones I interact with fairly regularly. "A" students typically come to class, ask questions, engage with the assignments, start their assignments early, etc. And before anyone accuses me of playing favorites, I don't do any grading, and grading is anonymized. But I can easily predict the "A" students just by their work ethic. The idea of the brilliant student who doesn't come to class and effortlessly breezes through the exam is as far as I can tell after teaching thousands of students a myth. At least at my university. Maybe all of those kids go to MIT.
Pre-pandemic I would give them a paper exam in which they had to read and identify bugs, or write code by hand. This was the tradition. Now they actually use their tools to the best of their ability, and I get to see what they are capable of.
You might think this testing paradigm would result in everyone getting 100%, but that's just not what I've seen. The distribution of grades the last exam was normal with a mean of 80%, pretty much in line with what I get during a typical semester. As we transition back to a classroom environment, I don't expect to move back to paper-based CS exams. They are just wrong on so many levels.