...is to pay the drivers while they are working for you. While waiting for fares, they're not free to do whatever, and should thus be compensated. That Uber won't pay their drivers while they're working seems criminal.
Cities like NYC require meeting certain utilization numbers which result in partially paying for time waiting for trips. The result of that has been that drivers are forced offline and to leave the airport when there’s an oversupply of drivers.
It would require uber to actually tell drivers where to go, which it doesn't do right now. Basically, completely change the model currently used.