Size does not improve the economics of delivery of the taxi service, 85 percent of which are driver, vehicle, and fuel costs; the remaining 15 percent is typically overheads and profit.
Uber was selling its services at only roughly 64 percent of their cost in 2017, with a GAAP profit margin of negative 57 percent.
As a reference point, in its worst four quarters, Amazon lost $1.4 billion on $2.8 billion in sales, for a negative margin of 50 percent.
Uber defenders might argue that that’s a big improvement from 2015, when revenues only covered 43 percent of costs, and the GAAP margin was negative 132 percent.
In its early years, Uber gave drivers high payouts to attract good drivers and also offered drivers incentives to buy cars.