Not sure if I agree with it in this form, as I think people can get by quite well without an explicit purpose. My grandparents were farmers, and I've never pictured them to feel any specific purpose. They were still content with their lives, as they simply didn't even considered the question of what their purpose was.
Modern success is all about fixating on a single measurable goal, and grinding that out. What if there is no single purpose but rather a diffuse set of meanings? Even worse, half the battle is you figuring out what this set of meaningful goals is, where before the goal was given to you (make lots of money).