Nationally speaking money spent per student is at an all-time high ($11,749 according to figures from Figures in the Statistical Abstract of the United States.) Yet we are getting worse and worse results. Private schools, on average, spend significantly less per student ($7,171 according to the same source) but achieve significantly better results.
Some school districts spend almost $25,000 per student which is drastically larger than all but a handful of the most expensive private K-12 schools in the world.
Money is simply not the problem and every single statistical number I have seen shows it.