Yes, I agree with you in part that they major mystics often abandon city living is to get away from the rapacious greed in city living, but regardless of how far back you want to go in history people have had to burn hydrocarbons for cooking, light and heating, and doing so produces air pollution, even on a small scale of hunter-gatherers there can be enough air pollution down wind from a fire to cause health problems for some people, then you concentrate a bunch of people into a smaller space life Mesopotamia, Egypt, Babylon, Greece, etc. and you could have some serious air pollution, which could be not just producing significant levels of chronic illness but possibly some collective insanity.
Meanwhile there is plenty of evidence that education as far back as you want to go in history has resulted in prosperity, consequently people have been buying their way through the educational system all along. I certainly witnessed it in the decade or that I spent in universities studying and doing research. So, we cannot conclude that education necessarily leads to the development of critical thinking.