(borrowing and lending, state borrowing and how banking work, not econ macro ideology) can easily be taught to 15 years old and it's not done.

IMHO, one of the issues about teaching/learning is that you need someone who wants to learn.  And sometimes, relating to myself in my late teens and early '20's, I didn't see the relavance of what people were trying to teach me, in many of my courses.  also some of my profs were unbelievably boring--especially some of the brilliant ones post undergraduate degree, who have written seminal papers and books on important finance topics like option pricing, money policy, etc.  

Maybe as an example of what I'm saying,  I didn't understand probability theory well until I started sneaking into the race track, horses, in my late teens.  I spent a couple of summers there, after I finished my shift at the factory, learning probablilities and odds.  Then much later in life I learned other things in statistics when I was in a position where I had to review manufacturing and quality control data--all of a sudden sampling techniques and all that r-squared kind of stuff made sense almost immediately, because It was helping me understand something I really needed to understand.  (Similar experience when I had to learn sales forecasting, and the importance of sales accuracy and inventory levels to customer service levels.  You know this kind of stuff and put disciplines in place, and your customers love you,,,,because your products are there when they are needed.)  But I could only vaguely get these concepts in school.

You need to relate these topics to people's lives, so they can become interested in them,,,,,and then make them fun.  I have an idea for an accounting book which I may write, because i think I know how to make accounting relavant and interesting.  But it just takes a long time to fit in writing.  But i think I'll get this one done in the next several years.  I have younger friends and younger family members that could really use it--even if I didn't get it published