(Note that I don’t have a clue what normal prices are. And trip price is not actually a linear function of as-the-crow-flies distance. Not insurmountable.)
I think it’s especially important to get this right because “fast pricing” (all pricing is variable, so don’t call it that) is so important, if we intend to take full advantage of the opportunities in market efficiency offered by the internet.
I imagine that one day, users will be able to place limit orders (“I want a ride so long as the rate doesn’t jump above this threshold in the interim”), or buy & trade options to get an Uber ride at a certain time, place, and rate. And so on. Ayup.