I went through 12 years of public school, 4 years of university, 4 years of medical school, 1 year of internship, 2 years of residency, and 4 years of fellowship. Then I joined the faculty of a medical school for 22 years. In all that time, I received only 3 hours of instruction in how to teach a class.
But where were those 3 hours given? In my Army Reserve unit, where all the officers annually had to attend a 1-hour training film on teaching a class. If I had not been in the Reserve, I would have received zero hours of instruction. And although teaching is one of the criteria listed for tenure and promotion, in fact the only criterion – at least in the sciences – is bringing in money from grants.
And even if teaching were used as a criterion, the word now would mean being woke enough. So don’t ask why university and graduate school teaching is often so lousy. They planned it that way.