Andrew Sullivan rounds up a few articles on why we love denim.
Any idea, any product, any design that people can act with, through, or on will be carried forward by those people; and they will love it when it is gone.
This is because a narrative starts with our actions, and is repeated back to ourselves.
Why do I wear jeans? Because I am the kind of person that wears jeans. What kind of person is that? A cool, comfortable American person.