Have they failed?

Or are they dutifully resisting cultural shift that threatens the "don't think critically, just go to work, pay your taxes, don't question the system, don't do drugs, go to college, get a job, lease a new car, buy a condo, cross your fingers that stonks go up enough for you to retire" late 20th early 21st century status quo "ideal citizen" and "ideal culture" that they were built to foster (and who are the kind of people who fill out the majority of the system)?

The way I see it peddling blue state bullshit and red state bullshit (depending on a given school district's location) is simply a common sense adaptation districts are making to garner support from local populations who were willing to support the system so long as it provided useful education at a non-insane cost but are more critical now that the deal is worse.

People choose based on grades, success stories, safety, and exclusivity, not political alignment. But public schools aren't competitive, so they don't have any incentive to offer any of those things. That makes them a useful and susceptible hot bed for the least desirable part of an education; politics.