In a lot of parts of America school funding comes from local taxes so regions would need to band together to provide consistent funding across districts (which would cause the richer districts to lose funding money which pisses off rich people).
Funding has nothing to do with the schools. A single disruptive student can shut down a class.
Within a school district, teachers are assigned. They rarely get the school they want. So for any given school, an entire district has the same pool of teachers. And yet some schools are much worse than others.
As I said, the rich people don't want it to happen... so it won't.
Additionally, people literally buy houses for the school district - if you start to disrupt that system you'll potentially cause a shift in housing values and then you're up against both the rich and property owners and America can't win that fight with its current political system - money carries too loud of a vote.