The focus shifted to teaching to the lowest common denominator. This was one of the primary reasons my dad retired a few years early. He couldn’t take being told by the HS principal that his classes were too hard (Advanced World History, US Government) and well that he couldn’t in good faith continue to teach about the US government as it no longer resembled anything like the Founding Fathers designed.
We know and history shows that lowering standards simply leads to lowering standards. It’s a vicious cycle that cannot be broken unless you raise the standards.