Like Uber replaced all drivers with self driving cars [1] in its 20 years of operation?

They're trying. I see Uber robotaxis almost daily.†

I haven't bothered to see if they're still in training or actually taking passengers.

† https://lucidmotors.com/stories/lucid-nuro-uber-partner

I know they're trying. Trying is not the same as succeeding, which was my point.