As someone with several family members and friends that are teachers and principals, the general opinion among them is that masks don't help much, especially in elementary school.

The kids are only required to wear them part of the time, and when they do wear them, they tend to wear ineffective masks, and wear them incorrectly. This results in making it mostly a waste of time and effort.

It's of no surprise to any of them that infection rates would be similar with or without the current regulation.