>Why not test this stuff? Standardized tests are objective.
Sure they are, but to what degree do they really reflect on the teacher? A teacher can be doing a fantastic, patient job with a student, and make zero progress all year with a student. That work is meaningful, but its effect could take years to show up. Can we measure this? Sure. But it will be very error-prone, and ultimately less effective than just asking the other people in the building who is worthless (everyone knows except the worthless themselves.)
We're not looking to find the best and brightest - we as a society have made the decision that we're not going to pay that much. We just want to get rid of the unequivocally awful.
Now, the current system focuses on meeting minimums, and most standardized tests quickly hit a ceiling. I'd much prefer to see tests that attempt to gage the entire breadth and depth of student learning. Practically, that's going to require different questions asked of different students, or you'll end up with a 10,000 question exam. But I still consider it standardized testing. The SAT and AP exams are great - we should do more of that earlier.