Did I miss something? I thought Uber was still a long way from being profitable and had no plausible plan for how to become profitable.
Uber is valued more for its potential and growth. Uber is optimizing growth and revenue before it optimizes profit (which could take another decade). See Amazon.
Uber is already withdrawing from Asian cities (eg Bangkok) where the price of taxis was close to cost, and in other cities (eg Melbourne), where Uber's flouting of the existing law has lead to deregulation, Uber is just another brand in the market. The price of a normal taxi hailed on the street and an Uber (I took Uber to/taxi from the city the other day, non peak, non surge) was literally within 5%.