Oklahoma's median income is well above the OECD average. It's nearly 40% higher than Italy. Teacher salaries in Oklahoma are accordingly higher. They're going to have to spend quite a bit more than Italy and Spain.
Regarding missiles. If we spent... $200 billion less on defense, which we easily could afford to do, the Federal Government could kick that money down to the states for other purposes (infrastructure, education, healthcare). And or the Federal Govt could lower taxes and the states could raise their taxes.