Teachers get a lot of (empty) praise in the US. But many of them allow bullying. Many ARE the bullies. I've known a teacher who sold drugs to students. I remember a classmate who was r*ped by a teacher.
1) teachers are not respected by parents, administrators and politicians, 2) so very few of the people that would make great teachers go into teaching
And in some states like California, it's very easy to become a teacher on an emergency credential. In the mid to late 90s when I was in school, most of our teachers were like 23 or 24 and were on emergency credentials. They were not the good ones.