K-12 education isn't going to make you "smart" by any high-level scholarly standard, in fact genetics may ultimately play a larger role in that than education alone.
The average IQ is 100; the average reading level is about 6th grade. (I'm in the top 1% in terms of linguistic ability, so I can attest to this).
If anything, K-12 education should concentrate more on practical or life skills; for example, the state and federal legal system should be a big component of education, given just how ignorant of the basics of the law many Americans are; there should also be a good amount of education in regards to conflict resolution, debating, negotiating, and other practical skills which are helpful in real life.
(This is where most of the super-rich make their money, from deals or negotiating with others, rather than from working for a salary).
If anything, historically there may have been less "formal" education (even given again how low a level K-12 or the bare minimums for colleges and universities actually is), and more emphasis on practical or work-related skills.