Instead of trains we're working on self driving cars. They better serve last mile and are better suited for private investment and innovation than huge infrastructure projects.
You also can't fit as many people in self driving cars, simply because having the requisite fuel storage and engine per 2-4 seater car is quite a lot of space when you can spread that around 200 people per train car. And this is before we consider that average car occupancy is something like 1.5.
