What if you could, like, delegate the entire driving process to someone? It sounds outlandish to pay for a driver, so what if you and a lot of others got together to take one vehicle. Perhaps some specialised vehicle where, through an economy of scale, it makes sense for hundreds to be moved by one driver. And for this economy of scale, what if you get the vehicle to go to places that makes sense for many of you at once.
It would make no sense for such a vehicle to be one rigid vehicle, so what if you instead make a chain of vehicles? Guidance of.... let's just call it an articulated hypercar.... would be challenging, so what if you build a road for it, where you could build the guidance into it. Since the path is now very predictable, you could even optimise the interface between your vehicle and the path for rolling resistance and speed, and build an electricity supply directly in your hyperway.
If you're driving a train its the same as if you're flying a plane. You're still responsible for the vehicle for the whole journey. If something goes wrong, you're expected to respond immediately and deal with the issue.
This is different from what a user expects of an autonomous car. We expect the car to handle and take responsibility of all of that, such that the driver is nothing but a passenger.
Even when automation reaches that level, the big issue will always be insurance. Even if autonomous vehicles have less accidents, that will only mean less revenue for insurance companies. And that's assuming they can pin liability onto the customer, rather than the manufacturer.
Between driving a train or everyone driving cars, there's a subtle difference between expecting everyone to do so individually or expecting a few to do so professionally.
I would not trust autonomous cars for the coming while. If Tesla cannot make autonomous cars work in a tunnel, built entirely for Tesla cars, used only by Tesla cars, then I doubt that within my lifetime, we'll see autonomous cars become good enough for the general public. And even if they do, they're one computer bug or cyberattack away from a motorway pile-up. And you can bet your ass that a driver in an autonomous car will doze off when he's got the chance, so you cannot trust everyone to drive a self driving car.
Besides, autonomous cars still have almost every other problem as regular cars. You still have two tons of steel, glass & plastic for one person to move around, supported on rubber tyres on asphalt, which is noisy, energy-inefficient and an absolute space hog. Now it's not the owner calling the shots as to where & how the vehicle is going, but a black box.