I don't remember specifics but it was less than federal minimum wage, partially because the area was over saturated with drivers and partly because the biggest cab route in the city is off limits to Uber.
A driver friend showed me his phone. His best was about $1800 a week. He said he has met people who have had over $2.5k weeks. The hours are horrible though.
I'd say the goal is not to maximize driver earning but rather to minimize rider pain. If drivers make more in the process that's great. If not, it is not our concern.