It's a reaction to the system within which we live. We must have money to survive and thrive, and thus the vocation to which one devotes oneself is, at the very least partially, driven by the need to feed, clothe, shelter, and entertain oneself. Passion is a luxury for the well provisioned or the uniquely ascetic.
Consider: How many of us would be writing software for a living if it paid like a fry cook?