I think you underestimate the importance of history for the individual and the ignorance of the masses. History isn't just about the conduct and decisions made by impactful world leaders of the past. The learning of past mistakes doesn't only apply to us collectively but also individually, nor is it limited to the mistake of a particular circumstance. People do not know if or when they may find themselves in situations that are similar to or related to historic events, therefore it is the responsibility of the education system to include the subject to prepare young minds for an uncertain future.
If the dictum 'history repeats itself' is true, uneducated future generations would have little to no knowledge or understanding of how to deal with it if they do not know the historic significance that brings the situation to the surface. A nation, much like America, depends on an informed and educated public, whom elects representatives and public officials to govern our country. Without a proper perspective on history, we are more likely to repeat past mistakes made by our nation and others. Even with the teaching of history, we are still subject to repeating the past because of the lack of emphasis and importance on knowing history. Those who are seeking power and a status of high authority are inclined to take advantage of the ignorant and naïve masses in order to get it, and impose their polices and agendas.
America is often compared to the Roman Empire, and has been projected to fall in pretty much the same way. The insertion of rhetoric and sophistry in public and political discourse allowed falsehood and partial truths to be accepted with the same credibility as truth, which is probably the most dangerous and subtle threat to any society. Not only is America repeating that very same mistake, we are also following in line with the Romans mistake of devaluing the currency. Because the masses are made up of a collection of individuals, however likeminded, we our accountable for taking advantage of opportunities to become educated in a broad and diverse respect.
Although, self-education and learning outside of educational institutions can help confirm and supplement collective learning, their is still the issue of the individual taking it upon oneself to do so. Uneducated people are easy to manipulate and control, and the saying 'ignorance is bliss' most likely comes from the people who are pulling the strings. That is why it is important for the powers in charge to change the narrative of history and or deemphasize it's significance. Getting rid of the teaching of history would be the optimal circumstance as there would be no point of reference or context for the public to go off of. We'd be pretty much making personal decisions and choices that impact others blindly on the fly, while authority gets away with deception.
Sadly, this is going in America right now. When government and the education system are in cahoots to revise the system to promote their agendas, history is one of the first subjects to suffer. This is why politicians support a conformist approach to standardize testing and education, and oppose school choice for parents and students whom prefer higher performing schools. Talk show host are conducting random interviews quizzing the public on basic elementary history and their historic knowledge as a gaff segment on their shows. If you were to ask all of those who failed the quiz whether they are susceptible to manipulation and indoctrination they all are likely to say 'no'.