First of all, I completely agree with your statement that majority of people are not very smart. That is why Democracy doesn't work very well and people keep electing populist leaders that are obviously peddling snake oil or complete BS to put it mildly. Like elect me and you will be winning so much that you will be tired of winning :)

And I don't think the main problem is that it is not very high on government agenda to educate people, the problem is that educating people is hard, you cannot make someone learn about interest rates and understand it if they don't want to. Plus educating the population means spending money for government, given it is a hard thing to do due to people not wanting to learn there are much better uses for the money...