The problem is payment. If you use the CC network, you're still getting tracked. Adding regular Bitcoin would not help much (most people would purchase them in a trackable way) but it'd vastly increase the difficulty in pushing for a switch.
The problem is the potential for dodgy drivers. No way in hell I'd get in a car that could be some random Joe Bloggs with no oversight. There has to be a central someone that says "this is one of our drivers" that can be held accountable.
This is why the Austin Thumbs Up! initiative matters and companies like ID.me with their identity proofing/vetting capabilities can solve the issue.