Uber has the data. They know all the trip prices, models of cars (costs can be calculated), and time that drivers are online. This could be figured out, but would you trust what they said?
My suspicion with some back of the envelope calculations is that it probably ends up somewhere in the minimum wage range most of the time. Especially at the higher end of that range, it sort of makes sense. Assuming at least a reasonable percentage of drivers have some rational handle on what they make and their real costs, that's about where you'd logically expect pay to need to end up.
To be clear, I'm sure some drivers don't really understand their costs or know that they're effectively borrowing from their future self who will have to pay maintenance bills--and feel they don't have an option. But it's a bit hard believing it's near universal behavior.
Your assumptions are incorrect. The world is filled with people who can't estimate costs, it's actually pretty difficult.
I've worked in online gambling before. I think it has a lot of similarities with Uber. It's entirely possible to have the vast majority of your customers lose money.
For budgeting, I’ve tried to just arrive at a cost per month of ownership for a car with expected depreciation (not cost to purchase), ins., gas, and expected maintenance.