That's nonsense.
I'm speaking from the perspective of a parent whose DCs went to a public high school in the US, a school with a very mixed student intake - a student body of 3,500+ from all sorts of ethnic backgrounds, income levels, cultural backgrounds, parents with wildly varying levels of aspiration and ambition and different experiences of school and school systems.
There were kids heading for Harvard and kids who wanted to be mechanics or hairdressers and all points in between. Many of the students were TESL students, from homes where Spanish or Polish or (lately) Ukrainian were the first languages. There were students whose ancestors came from the rural South whose experiences of segregation had an effect on how they viewed schools.
There were no uniforms, just a dress code.
There were lockers for every student, assigned on the first day of freshman year and kept for all four years, and PE lockers where students could keep their school issued PE shorts and Tshirts and leave their day clothes and bags while doing PE.
There was a five minute passing period between classes. Students could talk and use whatever side of the hallways they wished to use, getting around a building that is a city block long (1/8 of a mile) and four floors high.
Students could get a hall pass to use the bathroom during class. Hall passes were tracked.
Students were placed in academic tracks based on placement exams and performance in classes. They did not advance year by year with kids their age.
The library was specifically remodeled as a place where students could hang out, supervised.
Minor infractions of rules did not result in detentions or exclusions. A buildup of minor infractions resulted in a referral to a dean of discipline and a discussion of issues behind the behaviour, and problem solving. The school did not expel students and did not use detention as a constant response to chronic problems.
The school employed security guards to keep order in the hallways, cafeterias, and surrounds and to double as crossing guards/ direct traffic.
SEN were diagnosed and IEPs developed by SEN staff employed by the school. The school had a Special Ed section, plus a nursery for the babies and small children of staff and students, and farmed out kids who couldn't function in the mainstream school environment because of emotional or MH needs to specific alternative educational providers, with each student fully funded by the school, including school bus transport.
The school served breakfast and lunch in the cafeterias, with FSM students able to get a hearty meal at no cost twice a day, and reduced cost food available to hundreds more. During the covid shutdown the school distributed iPads and chrome books to all students and had free meals available for pickup to all registered for free school meals plus any other students whose families needed a weekly package of dry/ tinned pantry items - noodles, pasta, jars of sauce, dried fruit, instant porridge, etc.
Yes, all of that (and there was much, much more) costs money. If you think operating what amounts to a stressful boot camp masquerading as a school will accomplish what money and evidence-based approaches to discipline do, you need to examine what it is in your assumptions about your fellow Britons that makes you think that way.