It is part of the human condition, I think. The vast majority of people are afflicted by perpetual dissatisfaction, the continual desire for something different—this is why many people willnot eat the same thing for thier entire life, or even more can once per week. As I see it, perpetual dissatisfaction leads people to want things which they cannot have—this is the underlying reason why many of us like fantasy. As a further subset of that, some people latch on to ideals or people which they percieve as more accessible/probable than pure fantasy.
TL;DR: The less obtainable it is, the more we want it.
It is part of the human condition, I think. The vast majority of people are afflicted by perpetual d