I can't agree with this hard enough. There is an anti-smarts culture in parts of the US (in passing, this may not be about geography, but about social circles you/we exist in), and if you demonstrate your smarts, you are... other & alien. Things like having hobbies outside of a particular circumscribed area (sports, cars, $current_music, etc.) are the province of the "others". And when you drink from the cup of knowledge in an area, it simply becomes hard to stay in that place.

So we leave. We seek out the company of others in our particular in-group and revel in not having to be untruthful about ourselves. I'm reasonably sure this holds true about things besides intellectualism, but my readings in sociology are not close to deep enough to recite citations.