You're putting a lot of the onus on the student, when often times it's the state. I went to a high school that should have had 2000 students but actually had 3000. So crowded we all abandoned going to lockers between class in order to make it on time, and just carried full backpacks all day. Most classes had too many students for the teachers to really help actually teaching at.

That last statement came from one of my teachers, so happy she had one of the few classes with around 20 students instead of 30 plus. It was a world history class, and still the one I recall the most, more than 20 years later. She had the option to work directly with us on stuff we didn't understand, and had more interactive classes (like having students with specific relations to civil rights type stuff discuss their experiences in front of the class).

When you're an exhausted kid being taught by an exhausted teacher who can't even check up if you're falling behind, you don't retain much.