any discussion of the threat self-driving cars poses to Uber tends to imagine a world where there are magically 10Ks if not millions of self-driving cars everywhere immediately. That simply isn’t practical from a pure logistics standpoint; the time it will take to build all of those cars — and, crucially, get government approval — is time Uber has to catch up.

Moreover, it’s not at all clear that Google will be willing to make the sort of investment necessary to build a self-driving fleet that could take on Uber. The company’s recent scale-back of Google Fiber is instructive in this regard: it is very difficult for a company built on search advertising margins to stomach the capital costs entailed in building out a fleet capable of challenging Uber in more than 1 or 2 markets.

Finally, as the incumbent in the transportation-as-a-service space Uber has the advantage of only needing to be good-enough. To the degree the company can build out UberPool and UberCommute, they can ensure that their own self-driving cars get first consideration from consumers trained to open their app whenever they are out and about.