I think the idea is that those drivers will be less likely to work that morning/afternoon when there is a high prices night up ahead. Of course the means there are limited drivers on the lower priced afternoons, but it should work out as time goes on with more and more drivers signing up.
The problem with this is simple: the moment you set up a paid search service, you have to restrict access to those people who have paid the subscription fees.
How so? You're going to have all sorts of promotional access.
But if Goebbels' heirs don't have an exclusive right to the diaries, then what incentive does Goebbels have to write diaries? We must continue to grant and enforce this monopoly, or else Goebbels' lack of return for his hard work will cause him to give up and get a job as a dishwasher. Is that the kind of world you want to live in?!
Where there's a will, there's a relative.