This pervasive myth that it is a "not enough money in the system" does a great disservice to everyone involved and means we never discuss the REAL issue. There is tons of money, but the systematic problems are immune to money -- we could double spending and it wouldn't fix the issues. Parents don't care, teachers are protected by a powerful union so they don't care... student are treated as "must move" assets, standardized testing is held up as the be all, end all of measuring progress.
Instead of continuing to throw money down a blackhole that seems to not generate better outcomes, maybe it is time to rethink our approach... or admit that schools are tiny people prisons and useful filters and have very little to do with educating children, and more to do with segmenting and ranking them (which is useful, but can be done far more cheaply).