Assuming an average fare of 2.47$ per to make the math even, that's 6.00$/ride total cost.
When a company / government gets the cost per mile to run a fleet of autonomous EV's down to ~60cents/mile or so, which is a plausible enough number, then a lot of those transit rides are going to look real silly from a cost effectiveness POV.
Yes. If the government were able to provide transit more cheaply in the future by using new vehicles then the transit that the government provides would be cheaper than it is today.