Tech makes things like high-speed rail more useful, not less. Basically, app-based electric rental cars (self-driving or driven) solve the “last mile” problem nicely. And, computers or not, it’s a lot safer to travel 150-200 mph on rails or some other hard guideway vs on a road.

If the rental cars only need a range of 50-100 miles, they can be more efficient, since they don’t need to lug around a heavy battery pack. Also, making fewer batteries is better for the environment. The trains can pick up power en route from a wire, of course.

Also, if trains can also be “self driving”, you can make them shorter and more frequent since you’re removing the fixed cost of a motorman.

Unless we end up with flying cars, which would be terrible energy-wise, we’ll need some kind of surface infrastructure, whether it’s roads or rail. Might as well pick the kind that’s easiest to electrify and least environmentally wasteful.