Two things to consider.
1. The purpose of school: To produce a basic worker who wont question authority and to keep a large segment of the population out of trouble for a majority of the working day (babysitting). School hasn't really changed much since the late industrial revolution with the exception that child labor laws mean more kids stay in and complete school.
2. A typical high school student completes 25 year long classes in order to graduate. Those typically include 4 Math, 4 Science, 4 Social Studies, 4 English Language, 2 Foreign Language, 1 Art, 1 PE, 2 General Purpose (Health, Speech, home EC, etc) 4+ Electives (Sports, Band, Shop, Ag)
What are you going to get rid of to open up some time in the kids schedule to teach finance? You can't take away electives, parents and college like to see their kids involved in things.
If we are going to change the curriculum, are there not more important things to our society to teach? A basic medic class, philosophy, ethics?
I think a one year "Life Skills" class should be added. But the question is, what do you teach. I know too many people that didn't have some really basic skills coming to/out of college. Things like cooking basic meals, doing laundry, basic home upkeep (how to clean to basic maintenance), hygiene and self care, budgeting (this is where basic finance could be taught), or how to drive (for those of us in car dependent places).