It depends on what you consider as market in which Uber/Lyft operate. If it's entire personal transportation market, then one can think of them as in a zero-sum

It depends on what you consider as market in which Uber/Lyft operate. If it's entire personal transportation market, then one can think of them as in a zero-sum game with other players. I believe that the ride share market (even if you include taxis) is a growing market. Sure, it is very competitive so there is some struggle to gain market share, but there is also incentive to grow so as to get that economies of scale because whoever has that can price extremely competitively and be the winner.