As with many things, the solution is obvious. As you say, fund all students equally, from general revenue, ideally Federal as the Constitution requires schools, instead of local property tax revenue. Schools would be flatly equal (other than the usual overclass bunching up in their own enclaves to keep out the poor and dark), rather than the ton spent on the students in the rich areas from local levies and the federal and state underfunding the poor schools, which of course leads to the "failure" of the average test scores we see (richer areas have high scores, poor dead flat ruined, and the "average" drops).
Schools work fine. We just concentrate wealth on some schools and let everyone else go to hell, in the name of freedom. Whose freedom is the question.
This is the fallout of slavery, and lately of quietly letting the country fill up with illegal immigrants to keep wages down. In essence, we've been screwed for over 300 years because businessmen wanted to pay zero to almost zero wages and keep the profits.