system
Given the following post, respond as if you're commenting on Reddit:
human
My professor earned his PhD at a much more rigorous school than his current employer. He seems surprised about my class's lack of skills.

Hi, last year I took a machine learning class in my comp sci master's program.  The prof was a younger, fairly recent hire who earned his doctorate at a quite prestigious engineering school.  He is knowledgeable and a good prof, but I couldn't help but notice how deflated he got with our class's abilities.  He has talked many time about complex projects that he had to do as a grad student and then just assigns something much simpler to us.  In most classes, he asks what he thinks are basic questions about stats or linear algebra and is shocked when no one answers them.  When he is helping students with programming assignments, I can see how exasperated he sometimes gets and shocked at the basic problems students are having.  It honestly got depressing - because he clearly knows what level of rigor is needed to properly teach this class.  It also seems like he has to dumb down the material.  It makes me think I'm not getting an accurate picture what you need to know to understand ML.  I got an A and it wasn't very hard, but it also wasn't satisfying as I don't think I really proved anything to myself.

Is this something that occurs often in grad school?  In undergrad, I imagine it occurs less because curricula for classic subjects like (like Calc or Intro Physics) is fairly standardized.  However, in grad school with subjects in fast evolving fields, I imagine the prof has a wide latitude and the quality of education you get will vary widely by institution.
gpt
This is very common. PhDs don’t often get their first job at an institution as prestigious as the one where they did their degree. 

In fact, because the number of grad programs in a  given field is so much lower than the number of schools where they can be hired to teach, I’d venture to guess that most professors spend their whole careers teaching at schools one or more tiers below their alma mater. 

On top of that, people who get PhDs tend to have been excellent students in undergrad as well, so their grasp of what average students can accomplish isn’t so great to begin with. 

A good teacher will adapt to this over time and through experience get a better handle on what can be expected. But it can rough on the students for the first few years. And sometimes they just become bitter, condescending assholes, ie bad teachers.