The top reason why public schools suck in the U.S. is because of politicization of education. That's why there's more bureaucracy in public schools today than 30 years ago. That's why there are more derivations of school boot titles, where school boards are literally line item vetoing history books to emphasize/deemphasize actual historical facts, and with science. Regional schools are not all on the same page with the same standard, or even the same agreement of how the world is or should work. People move to specific neighborhoods to go to specific schools, and that results in far less diversity today with more small schools than fewer big ones.