That defeats the selling point of Uber, you don’t just get a ride in one tap knowing how much you’ll end up paying anymore, unless you’re cool paying whatever the driver feels like they should be paid. Maybe I’m misunderstanding the idea though.

I think the idea is you’d put up your trip and what you’re willing to pay, and drivers would “bid” on it (the app may do a bunch of this automatically for you, the driver could set rates etc) and then match you with the “best” offer.

You enter A to B, you choose the driver based on what you wanna pay.

We had that, in the form of Sidecar, whose model lost to Uber et al in 2014.

I won't attribute a whole company losing because one feature, I still see it as a valuable option.