This doesn't surprise me at all and it's because of hidden costs incurred by the driver, combined with an implicit bidding system that drives down wages.
Hidden costs:
1. Vehicle wear and tear (cars cost you money when you drive them)
2. Vehicle depreciation (cars cost you money even when you aren't driving them)
3. Interest and fees associated with auto loans and leases
4. Insurance premiums
5. Gas
6. Unexpected/unplanned for tax bills
But the feedback you're getting about your income is just the dollar figure that shows up in your account, which is vastly higher than the true amount you could reasonably keep as profit. It makes $10 feel like $100.
Combine that with the implicit bidding system. And by this I mean, market forces will naturally saturate Uber and Lyft with drivers until the price falls low enough that drivers won't accept it. And because of the factors I listed above, that natural price point is practically guaranteed to be well below minimum wage.
The whole setup is just beautifully engineered to trick poor people into thinking this can be a career. I've often thought about which is worse, this or Herbalife. I think Uber and Lyft might impact more people than Herbalife, and generally those people start with less, so I might give it to Uber and Lyft.
Actually, it's also a profession that has one of the highest rates of workplace fatalities, so I'd definitely give the title to Uber/Lyft over Herbalife.