If you listen to corporate media, you might believe something for which there is little evidence: that teachers unions are what is wrong with public schools today.
There is much more evidence that what makes schools work or fail are societal forces that exist outside of school, especially poverty and income maldistribution.
Income inequality correlates strongly with school achievement. Schools serving rich children amazingly! are doing just fine. Of course they have not had to cut their curricula to the bone, oh no. Rich kids have music, art, drama, sports, tutoring when they need it, and vacations to Europe and Asia in the winter, spring, and summer.
School serving many of the rest of us are struggling to do much more than test prep..... School like mine have parent organizations and foundations to raise enough money so we can avoid cutting all the so-called enrichment activities from the school day.
The article you can read here goes into greater depth on this.