Here’s a thought for you. What percentage of the population wants to be mathematically literate given the amount of effort needed to gain that literacy? In my 30 years of teaching math at the college level the anecdotal evidence I have is that this number is quite low. Why do you think the number of mathematically literate people should be significantly higher than what it is?
What methods of teaching will work for those who don’t want to do the work to be mathematically literate?