Two things that I can see. One is that the COVID quarantine, while necessary for public safety, set most kids back developmentally at least a year, often two. It was far worse for younger kids than older kids because Kindergarten through 2nd grade are absolutely foundational points in their education. Kids who don't get a solid grasp of reading, spelling, and arithmetic at this point sometimes never catch up to where they should be. Hopefully my son will.
The other is that around the time my son started at the school, they got rid of the special education (or whatever is the correct phrase) classrooms, laid off those teachers, and put the students in regular classes instead. This is going about as well as you'd think.
The kids with emotional issues do not get the special attention and resources that they need, and the rest of the class is severely disrupted to the point that almost no learning gets done. According to my wife who works at the school, his class this year had four special-needs students in it. My son says that these students were constantly disrupting the classroom. They bullied the other students, they verbally and physically fought with everyone (including teachers), they scream when they don't get their way. The teacher is not allowed to send them to the office or another room. The whole class didn't get recess for over half the year because the teacher couldn't handle the kids outside. (One of them would just run right off the school grounds every time, apparently.)
The school used to have a strong positivity vibe and a zero-tolerance anti-bullying policy. Now, when an emotionally-troubled child draws blood on my child (which happened), the response from the faculty and staff is so silent it's deafening.