I'm not arguing that state and local levels don't have any impact. There's no doubt that they do, but imagine if federal funding was double or triple what it is now. The outcomes could be so much better, even in places like MS where the government is actively working against its people.
Edit: I also agree with where you seemed to be heading, which is that there should be some national minimums both or education content and how funding is spent.
I reviewed a bunch of sources from a quick (and not extensive) search, and it looks like it may vary by district, but I'm seeing sources (across different years) with averages as high as 13% and as low as 8%. I don't know where I was getting my number, but I thought it was more like 43%. Even 13% is shite. 8% is abysmal. So sad.