pineapple95 I agree with you 100%.
My DCs went to a K-8 (age 5-13/14) elementary school in the US. There was a preschool for 3and 4 year olds too, and all day wrap around care for students from 3 to 13/14.
Parents were not allowed to accompany children into the building, even at age 3.
Children lined up outside the school in the morning and were marched to the lockers outside their classrooms by teachers (3, 4, and 5 year olds had cubbies). They took off their outerwear and boots and class started promptly at 8. In the afternoon, they all put on their outerwear (including heavy duty winter wear when it got bitterly cold) and left the building, to be greeted by parents/ caregivers at the doors. Children were not released until the teachers manning the doors recognised the individual picking up the child. Each class always exited at its own specified door.
At lunchtime everyone in the building all day managed to get lunches and outerwear out of lockers and proceed to the lunchroom in class groups, suit up for outdoor play in all weather, and got back to their classrooms again for a prompt start to the afternoon schedule.
If you had forgotten your lunch you could get a sandwich in the lunchroom, or your friends might share their lunch with you. The school discouraged parents from bringing forgotten lunches. If you wanted to bring a lunch you could drop it off at the school office and the student would be paged to go and collect it at their lunchtime.
Full size lockers for every student meant you could stow your gym stuff, your art stuff and your outerwear and boots in the locker so nobody was left carrying bags of gear around the building all day (from 5th grade on all students moved from room to room for different classes) or looking like a pack horse on the way to school or home.
Children up to First grade (age 6 turning 7 average) wore their gym clothes to school on gym days. Gym clothes were shorts, t-shirt, sweatpants, sweatshirt depending on weather. This meant no time wasted changing and no loss of uniform items.
On Thursdays a folder was sent home with the oldest or only child from every family, containing information for the following week, any permission slips to be signed, and notification of money due for various events or collections. Parents sent the folder back on Friday, signed,and with any paperwork enclosed.
You could talk to the principal or to a teacher by phone, by email, or by letter. They always got back to you by the end of the next day at the latest. Parents did not buttonhole teachers at the doors because they were there doing a necessary job that involved the safety of the children and they knew that they could say whatever needed saying privately on the phone or by email.
The school ran like a well oiled machine.
Boundaries were respected all around. Everyone did their job and nobody trod on anyone else's toes.
It was great.
(I actually don't know a single school anywhere near me where parents can enter the building during the school day unless they are volunteering for some activity.)