(a) is fixed because there's probably no-one for the Texan to talk to on the bus. For trains, the person to talk to is on the platform, and can simply let the train depart (example: Copenhagen Metro, although good luck spotting any staff).
It could be more easily fixed by accepting foreign credit cards (Gothenburg manages this, London if the card is contactless) or telling drivers not to wait.
(b) is partly solved if the cost of running buses/trains is significantly reduced, as that leaves money for extra vehicles.
Already many cities today operate busses by taking unemployed people and forcing them to take the job as bus driver for no pay (they'd have to continue living off of welfare), otherwise they'd lose 50% of their welfare money.
That's how you get bus drivers for free — automated vehicles can't really beat that.
It could be more easily fixed by accepting foreign credit cards (Gothenburg manages this, London if the card is contactless) or telling drivers not to wait.
(b) is partly solved if the cost of running buses/trains is significantly reduced, as that leaves money for extra vehicles.
(c)... well, who will notice?