This is a bad analogy. Webvan failed because they had huge CAPEX needs. In contrast, Uber has relatively low overhead requirements but they are spending heavily

This is a bad analogy. Webvan failed because they had huge CAPEX needs. In contrast, Uber has relatively low overhead requirements but they are spending heavily on immediate and future growth. They doubled revenue from Q1 to Q3 which is incredible. Sure, costs nearly doubled but they're not buying cars, they're not carrying drivers as employees, they don't need office space and warehouses in every city they operate in. The fact that Lyft burns through less money is an indication that Uber is pushing for growth over profitability. Finally, they just need to dominate the market long enough for driverless cars to become a reality. At that point their profit margin with 2x-5x and it will be easy to finance the cars with debt.