You've mentioned $1 a ride a couple of times. Where is this number coming from? It doesn't pass the smell test to me. Even bus fare is several times this amount.
Say initial cost of the electric self driving car is $50,000. It has life of 20 years. After 20 years, value will go to 0.
Per year: $2500
Service per year: $2500 (HN mechanics, is this reasonable?)
Miles travelled/ year: 50,000 (5x human utilization)
Miles/Kwh: 3 (based on tesla efficiency)
Avg electricity cost in US: 12c / Kwh
Cost to drive 50,000 miles: $2000
Total / year: $7000
Cost per mile: 14c / mile
Average trip length: 7 miles
Cost per trip: 98c (very close to $1)
I think this is definitely possible.
Not for electric self driving cars which optimize for safety and wear and tear. They have less moving parts too.
There are plenty of trucks, buses and taxis that have done a million miles in 20 years.