>they need to be able to understand and reason critically about the world.
The problem with that, however, is that there's a large proportion of the population that quite simply isn't capable of doing that (or who are located where those skills are irrelevant).
They're just usually hidden from the sight of people that are, in the exact same ways and for the exact same reasons that people of different political leanings self-segregate.
The American upper class needs to find a way to make the American lower class objectively useful again. Let-them-eat-cake "just get An Education and it'll magically make things better" is not helping the people who plain aren't smart enough to get a good job any more. An objective-focused education that trains an individual to be useful at doing a certain class of tasks (like fixing automated machines as they break), however, does.
20th century American history (as well as Maslow's Hierarchy of Needs) demonstrates that society cannot advance until _everyone_ has a sense of purpose and food on the table. Since the balance of political power in the US skews rural (lower class dominant), those in urban areas (upper class dominant) need to work harder to keep things equal.
And when everyone's happy, progress happens fast (though it tends to lag about a decade behind). Civil rights in the 60s, sexual revolution in the 70s, objective gender equality movements in the 70s, EPA in the 70s (and sufficient political goodwill to get the Montreal Protocol implemented), technological revolution in the 80s (read: automation that anyone could afford to invest in).
Progress has slowed down after that. Modern education has obviously failed to provide the educated with the critical thinking skills necessary for them to understand why, but that's a topic for another day.