Well you have a lot of people chipping in for Uber to be valued at $41G. While that doesn't tell us much about each actor's rationality, it does indicates that

Well you have a lot of people chipping in for Uber to be valued at $41G. While that doesn't tell us much about each actor's rationality, it does indicates that some people think there's value in the company's future. I can personally imagine a world where I don't own a car and pay 300-500$ a month to a company such as Uber so that a robot comes drive me from A to B whenever I want.