I don't know how economics escaped basic elementary/middle school curriculum. There is so much confusion in people's lives around money, and so much destruction that results from it, yet we still don't teach the basics of what is going on in school. It's totally perplexing to me.
Most people aren't capable of understanding numbers: https://politifact.com/factchecks/2020/mar/06/msnbc/bad-math.... You can't educate them to do it, any more than you can educate your average person to be able to reliably hit three pointers. It's a physical limitation.
That's why socialization is so important. You can't get voters to understand the difference between billions and trillions or put anything in context when the numbers get that big. All you can do is socialize them from an early age to have directionally correct gut feelings like, "there's no such thing as a free lunch" or "saving is good."
Scarcity of instructors competent to teach such subjects? Followed by the natural bureaucratic response: Pretend no such need exists.
Destruction? It's by design:
"One man gathers what another man spills."
If calculators had never been invented then perhaps arithmetic and economic literacy would be required of citizens. A big problem is that we invented a tool for something that's most powerful when you can do it easily and constantly in your head. People are not pulling out the tool to use it constantly because there's friction to that.
Economics class is usually in high school and it's optional.
Schools are really expensive to operate. Most districts and schools make it easy to graduate to maximize their graduation rates. Standardized testing is suppose to catch local lowering of standards but state departments of education are also under pressure to maximize test pass rate. So resources flow into pulling the bottom quintile of students up to a minimum standard. This means teaching to the test on math and English, and de-prioritizing other subjects or dropping them entirely.
We could expand the breadth of educational basic standards. This would require a cultural shift in valuing formal education more, increasing teacher training/recruiting resources, making schools year round, more centralization of education budgets at the state or even Federal level.
Generally speaking public schools tend to be better in states like Massachusetts than Kansas.