Keep in mind that teaching is its own skill. Especially in universities, that skill can get awfully specific awfully fast. In particular, for a TT professor at

Keep in mind that teaching is its own skill. Especially in universities, that skill can get awfully specific awfully fast. In particular, for a TT professor at an R1, odds are extremely good that they've NEVER taught anything below calculus and may have never even been the instructor of record even for calculus courses! They were hired to do research and teach graduate/upper-level undergraduate courses. Teachers that know how to explain and assess everything in a graduate analysis course with perfect clarity might not know how to handle the situation where a student doesn't know what it means to "show you work" in the context of calculating a derivative or solving a linear equation. In fact, they might not have even thought about learning/teaching that material themselves since early high school or maybe even middle school. This doesn't make them a bad teacher. It just makes them a bad calc I/college algebra teacher. Which is okay -- teaching those courses is not their job and is not what they were hired to do. So this is somehow a bit like complaining that a web programmer isn't particularly adept at kernel hacking. That doesn't make them a bad programmer, it just means they focus is elsewhere. Again, most universities do hire experts in teaching the lower-level courses. They're just not typically tenure-track professors.