The QC alone makes Uber’s business model viable. Holding drivers accountable with ratings makes Uber worthwhile at a premium over regular cabs, and significantly expanded the market. The only real risk at that point would be Lyft, the company that started the price war in the first place.

Uber may or may not be subsidizing fares, but they’re also spending tons of money on engineering and product development, both on their existing product and in an attempt to develop self-driving cars. That’s growth.