Michael Caution has some interesting thoughts on people who give up believing that ideas matter. You meet these people all the time. Philosophy is just an ivory tower matter to them; it has nothing to do with day to day living.
Modern philosophy, especially the analytic school with its technical jargon and focus on individual words, encourages the idea that ideas do not matter. Of course, the idea is much older than modern philosophy. The purest expression of the mind-body dichotomy is still Plato. But I think the single most important contributor is the split between morality and practicality in altruist ethics. People are taught to equate morality with sacrifice, but then they go about their lives earning money and pursuing happiness. They learn to compartmentalize: ideas are one thing and day to day life is another. Philosophy is at best a Platonic ideal that has nothing to do with life on this earth; in the meantime we are stuck in this reality with our hormones and our hungers, our human frailties that make us incapable of living up to ideals.
Shakespeare, of whom I wrote a recent post, does not believe ideas matter. When a character such as Brutus or Ulysses espouses philosophy, he is then shown to be a hypocrite or tragically misguided by his ideas.