Small class sizes don't just help, they are essential for this type of setup, which is why it can never work at scale and will not be relevant to 99% of kids in the country. There simply aren't enough teachers.
Their easily could be, we just can't imagine as a society putting this much effort into caring for the young. Especially those of the wrong skin color. The US is the wealthiest country in the world, we could easily change some of the governments wealth distribution to educate all students 8:1
Still no. You would need to triple the number of teachers and greatly increase the number of rooms across almost all public schools in America to get those kinds of numbers. There simply aren't enough people, or enough space to do so. The only viable solution is to find a better way of educating children in these larger groups.
"There simply aren't enough people, or enough space to do so."
The people part is the issue. The teachers I know hate the bureaucracy and policies. Private schools seem to be better at hiring, even when they pay less. Dealing with certain parents is a nightmare too.
If you have a classroom made for 25-30 students, it wouldn't be too hard to partition it in half, then have two instructors leading each half of the room.
I went to a robotics class and a game design class as a kid and they both had something like 20 students with two instructors. It went fine. Sure some of it was introductory instruction, but then we'd build our own stuff as individuals or teams. So there might not need to be much reconfiguration at all.
Increase teacher salary to $100k a year and cap teacher to student ratio at 20 and see how hard it is to hire them. I'd go straight back to school to get a teaching cert to change careers, even though it'd be a pay cut. Imagine getting the best and brightest people pounding down the school doors to teach. For reference, that would triple the starting teacher's pay at my local high school.