When the pandemic hit and schools were closed, the classes got on Zoom or specialized distance learning apps.
Teachers who were tired of teaching the same stuff to multiple classes a day began to pre-record their lessons and play them back for the classes.
They used the extra time to focus on helping the students with questions or problems with the material.
Students were doing better, and parents figured out which were the good teachers and which were the bad ones, demanding that they be fired.
The unions caught wind of the whole thing, and shut the whole system down.