I think growing up is also partly to blame. When people are younger, they have all these dreams and curiosity. But as they grow older, a lot of things get in the way of chasing them. Bills, responsibilities, work, etc, need to come first if they want to live. But that isn't to say no one is able to continue chasing their dreams and curiosities. There are those that incorporated it into their life. Researching for the cure to cancer, astronauts and rocket scientists curious about space, etc.

For the regular people that didn't pursue their dreams, they can still have the desire to explore, by trying to improve a system, studying and training to get promoted, and making the world a better place for their children in their own way.