Another education revolution was the requirement of special needs funding. The Supreme Court mandates that schools start funding special needs education is necessary to given them the same education level. (When you fact out this number, the difference between private and public education costs becomes a lot less.)
This constricted cash, but, because the per-student costs were still rising, and the property tax payers were still largely sending their kids to private school anyway, there was no political will to compensate for this cash crunch. So classroom sizes climbed higher and higher. Theorists came up with radical notions like “Whole Language” and “Phonics.” Diminishing returns on Our education investments, and misinformation about what was happening in the public schools of America being spread by those who see public education as a ‘liberal’ goal. So the majority of American parents is satisfied with their kids schools, but think American education is awful overall.
The reality is that conservatives have been wrong – you can throw money at schools, and they do improve. All efforts by liberals to get schools to improve have been in the face of the money crunch, looking for clever solutions which don’t really exist, and, yes, pushing around loaded political issues to gain favor with beaurocrats.