That makes the price knowable, I don't think that's the same as fair.

Lyft and Uber will both tell you if the price for the ride you're requesting will be higher than usual so in that sense their prices are just as knowable.

I think a fair price would be one that an informed and unencumbered buyer and seller reach. One reason why it can be hard to get a Taxi in New York if you're trying to leave Manhattan is because the prices aren't always fair and that drivers would rather seek a fairer transaction (in contravention of regulations).