My anecdata indicates that about a third of the drivers that customers interact with, however, have driven for a year or more. That's just my personal experience and may not be representative but I'll bet they have a bell distribution where there's some minority working most of the hours and making most of the money and a long tail that's either trying it out or fucking around.
It's also worth pointing out that at a median profit of $3.37 per hour per driver, Uber lost $4.5 billion dollars in 2017. Lyft lost $600m. Uber claims 327,000 drivers right now. Pay them an extra $10 an hour to get them up to something that isn't heinously insulting and their losses per hour go from $500k to $3.8m.
You know it's a weird world when VC firms are subsidizing your trip to the airport.