Teachers can't do anything about unruly children except call the police. A whole class has to slow down to accommodate the below average kids. We spend our first year in school playing around and singing the ABC song and drawing purple and green dinosaurs. Educational science has advanced far beyond the Prussian model, but we have to navigate a bureaucracy to change anything, there's no way to keep up. And their chant is "we can fix it for more money."
We live in a time now that you can access any and all information that is known to the public on a whim for free. This is very new for us, so people don't know what to do with it. You can, right now, with just a laptop, give your kids an education that even 2 generations ago most people didn't even know enough to be able to dream about, for free. You can educate yourself on any topic to any degree of depth that you like. Institutional education is obsolete. People will be competent from now on to the degree their parents care to teach them. That is with or without public schooling.
I'm putting together an education plan for my infant son, that I intend to release to the world once he has had a little go at it, for free. It uses FLOSS software and publicly available information, I'm going to rely heavily on Anki. I intend to teach him how to read starting at the age of 2, and I expect that by the time he is 5 he will have a handle on reading, a decent vocabulary, and basic arithmetic at least, I'm shooting for basic geometry as well. Writing and typing also. My goal is to have him educated at a high school level by the age of 12, with just 3 hours a day of "schooling." I'm pretty sure I can do it, the bar is very low.