To me, education should be about learning/gaining skills and knowledge useful for life after K-12 and learning to think critically and ****. But in my experience in the school system (and from bits and pieces I've heard from others), schools care more about money and status than actually educating the youth. It just cares about standardized test scores and graduation rates.
(sorry but this will be long and full of education policy stuff)
That goes to the Growth vs. Proficiency argument. Lots of public schools opt for proficiency instead of growth because it's easier to measure and measurements (like, for instance, graduation rates and class attendance) are how public schools traditionally get funded.
The tl;dr of growth vs. proficiency is that that proficiency sets a single standard and measures how many students meet it. For instance, how many students can pass Algebra 1 by the last year of high school. Growth measures a student against their previous abilities. For instance, how many Algebra 1 students move on to Algebra 2 regardless of what grade level they are in high school.
The trouble with proficiency-based education is that if you're at the top or the bottom of your class you get no help. The top stroll through and don't improve. The bottom are given up as lost causes. Not always, of course, but that system allows or encourages that kind of mindset.
The trouble with growth-based education is that people aren't that used to it and think it's not "real" education and is just babying kids. It also means you have to give attention to all the kids and help each of them grow. That takes more time and money.
The money thing is also pretty key when talking about the American education system.
Public schools (the American definition, that is, ones paid for with taxes and set up by local governments and which are free to residents within the school's district) rely on funding from a variety of sources, but a lot of it comes down to attendance. The more attendance the more money the school gets. The problem with that is that now with our newly minted Secretary of Education the push for school vouchers (some amount of government money taken away from public schools and given to parents who may opt to use it on private, religious, and/or charter schools) will get a lot more muscle. That would take away money from public schools because many parents will "want their kids to have the best education" and will try to shop around for something besides the default public school. Why this matters is that it lowers the attendance of public schools, which lowers the funding they get, and that lowers the quality of those schools. And maybe you might think that's not so bad, but the other options aren't really all that better. Charter schools are often for-profit and don't have the same rules to follow. They could, for instance, kick a student out more easily and still keep voucher money. They also share a similar problem with religious and private schools which is that they lack oversight and could, for instance, teach creationism to kids as fact. Charter schools are also not likely to be set up in rural areas where there is no incentive for them to set up shop (a.k.a no money). Private and religious schools are also still going to be too expensive for a lot of people because voucher programs won't be enough to cover the full costs, so all it would do is allow a few who are economically on the cusp of being able to attend while subsidizing families who already have means, leaving only even-less-funded public schools and charter schools, and charter school students do no better than public school kids and sometimes do worse.
So while we might all not be happy with the school system we have now, it could be a lot worse in the near future. The public schools which only teach to the book will have even fewer resources to focus on helping each kid learn. The less-regulated private, religious, and charter schools could be teaching kids not to think critically while feeding them misinformation or religious dogma - if you can even afford to go to one. There will probably be a few places that rise above this - good, affordable schools that give students attention and instill in them the drive to succeed and learn - but they'll be pretty few, and parents will savagely tear into other parents to make sure their kid gets the chance.
Race to the bottom.
tl;dr public schools have lots of problems but if we funded them well and didn't demonize them and teachers we might have better schools instead of this push to take your tax money and give it to religious schools