The survey was done by MIT and is highly questionable. They revised their results twice because their methodology was faulty. The average went from $3.35/h to $8.85/h to $10/h.
The drivers that are losing money are doing it part time, or are students and most likely working at the least profitable times of the day when the rates are at their lowest. These drivers drop out of it within a few months.
If this holds to Pareto's Law, approx. 20% of the drivers will produce 80% of the revenue. It is the same in other fields, sales, inventory, sports.
There has been some mention of the driver being declared employees. So far, all the court tests, one federal and several states, have shot it down. Even CA has tried but the state seems to have backed off. Uber's HQ is in SF, so there could be political pressure being applied.