Just for comparison - where I live in Australia, private schools do get limited government funding - nowhere near as much as government schools, but it does mean that it’s a lot easier for parent to choose private schooling if that’s what they want.
And it does, undoubtedly, improve education. The idea has become one that is supported by all sides of politics because it so clearly works well.
We’ve also had stimulus funds pushed into schools recently - again, private schools getting a share of that money. I’m not sure it’s done much for the economy, but it is making some difference to some schools and some kids.
America’s system seems so anti-choice from our perspective. And that’s unusual - normally it’s the other way around.
The goal of government owned and union operated US schools is not education, it is Leftist indoctrination.
Those who think the goal of American K-12 education is to produce educated students also think the goal of the UAW is to produce fine autos.
America’s public school teachers are one of the last remaining large groups of unionized workers. They support democrat policies with their dues and with their advocacy, so they are a very protected species.