The unfortunate trend I’ve witnessed in newer schools in my neck of the US (west) is to essentially make them fortresses, a place where entrances and exits are tightly controlled and each classroom can quickly be locked down. They honestly feel like prisons.
We all remarked on the classroom during back to school week this year for my third grader with “wow, you get an actual window this year!”. Other classrooms in the school have no windows or natural lighting at all.
One guess as to why this is becoming the norm.