I mean the teacher's unions have been screaming about smaller class sizes for decades, let's give it to them.
Private schools in the US look artificially good in terms of both finances and performance because they end up selecting the more privileged students to start with.
Maybe i could even alternate every year so they are "well rounded".
And someone's probably going to respond "but muh socialization!" In what other real-life scenario are you going to end up with a bunch of people who are almost identical in age, with little to no responsibilities, regurgitating shit with no incentive other than that you have to be there, or else? You don't. After that, it's off to either real school (university) where people are all at various stages of their education throughout their life, chasing education in fields that actually benefit them and the rest of society; or they work a job where there's even more diversity and generally less interaction with people.
Lower school is an alien place to be, and always has been.
You don't improve if you aren't answering to anyone. If they're threatened with money loss you better believe they're going to start doing something to make their school more attractive and that's how it should be. Right now they can be absolutely abysmal at educating anyone and still receive tax dollars.