I can't find the post, but there was a 'UBER finance guy' (self-claimed) on HN a few weeks back that 'spilled the beans' and quit on what Uber is actually: a sub-prime auto loan company. Again, this is my recollection, take it with salt. It goes like:
Driver (D): I want to drive for Uber!
Uber (U): Sure! Do you have a car that is safe and less than 5 years old? (I have no idea what the car reqs. are)
D: No
U: Ok, well, we can loan you one! Just sign this!
D: Great! I signed! What are the loan repayments like?
U: Well, you owe us, per the 3 year contract, $100/week (I have no idea what the actual loan terms are like, but 100 is a nice round number so lets use that)
D: Ok! That's not bad!
U: It gets better! We'll just auto-deduct the money you owe us from your driver's account, after that, all the money is yours! You don't have to worry about any of it, just drive for us, we'll take care of it.
D: Cool! What happens when I get sick or something and can't drive?
U: Well, then you still owe us the money, plus a 10% fee on that week's loan payment (again, I have no idea what the loan agreement is like, YMMV) that we'll automatically tack on to the next week's loan payment.
-A week goes by-
D: Oh man, the weather was great this week, not a lot of people needed me to drive them around! I only made $90!
U: Ok, well, per the loan agreement, you owe us $10 more then (100-90=10), plus the 10% late fee, making your next week's payment $100 + $10 + (0.1 x $100) = $120.
D: Oh man! I better hope that the weather is bad so people want to take an Uber that I am driving!
-Another week goes by-
D: The weather was really rainy, but even still, I only got notifications to pick up $90 worth of people! Not again!
U: Well, now you owe us $120 - $90 = $30 plus the 10% late fee on the $120, making your next week's payment $100 + $30 + (0.1 x $120) = $142.
D: Well, darn, I thought a lot of people wanted to take Ubers! All my friends take them! But I don't get enough notifications to pick people up from Uber!
U: We know. We are the people that are giving you a loan and simultaneously are the ones that control how much of that loan you can pay back because we are the ones that tell you how many people you pick up and we also set the 'surge' rates and regular rates that we tell you. Also, we have something of a history of acting in morally reprehensible way without shame.
D: Wait, what did you say?!
U: Nothing! Nothing at all! Get back to driving! That car we bought isn't going to pay itself off, you are!