I really don't blame the schools, the teachers, the funding. I blame the cultural shift where the schools are treated as daycare facilities and students aren't properly punished for failure or motivated for success. Hell, a lot of the time it almost sounds like a point of pride on the part of students to refuse to learn.
Perhaps anything beyond the 8th grade should be voluntary college prep, and students are admitted into it on a competitive basis, and kicked out rather swiftly if they prove a waste of resources. Everyone else can do vocational training until they reach the age of majority, rather than forcing them to learn academics they are already opposed to learning.