Other than constant facial recognition via camera pointed at the driver, how does anyone (not just Uber), guarantee that an approved driver doesn’t get out of the car and a non approved driver get in and start driving?

Perhaps a selfie with the driver taken by the passengers during the drive would also suffice.

In my opinion, Uber has done enough. They provide the passenger with the drivers name and photo. It’s up to the passenger to verify, but Uber should make violations easy to report.