If that were the case, countries would compete with each other and we'd all copy the best country. But it doesn't work that way. We know which countries are good at education (they mostly exist in Asia) and we don't even try to copy them. I suspect a system where each state set it's own education policy would work the same way. It's just in that case, this problem we have where people don't know US history would get worse when states just start rewriting history and teaching it. I can think of a few southern states that we can almost guarantee would do this.