I continue to take the view that the introduction of self-driving cars will lead to Uber being brutally cut down by disintermediation.
An AirBNB for self-driving cars will be as cheap or cheaper to operate: no overhead for managing or paying drivers, no need to invest your own capital upfront to buy cars or loan money for cars. You just connect car owners to people who want to rent their car for 30 minutes.
Even better: No need to subsidise fares to undercut competitors, just let your owners pick whatever price they like. Most of them will underprice for wear and tear, just as they already do, at no cost to the company making the connections between owners and riders. Meanwhile, Uber can't really ignore depreciation or wear and tear, even though it tries to place them at arm's length through loans to drivers.
The economies of scale in such a market are weakened. Sure, you can buy a giant fleet of vehicles at a discount. But your competitors don't need to and will never need to. And if your competitors have massive piles of their own cash, which they don't need hype to acquire, you're looking at a fairly brutal car-wreck.
Lyft won't kill Uber. Google Lifts will.