The industry is big enough for multiple players.
(For example: Why wouldn't an airport charge local cab owners a small fee to be listed in their registry? Why wouldn't passengers access that registry to save $10?)
That could be another aspect of first-mover advantage: no latecomer will have the same opportunities for regulatory capture that Uber and/or Lyft will have.
It's not a question of if the taxicab incumbents will lose their grip on the regulatory process, but when. Whoever takes their place will be able to shut their competitors out, or at least make life hard for them.
If Uber and Lyft run out of profitable ideas, and only have "reduce costs" left as a means to more profits, THEN it's a commodity.