Fast Trains cost much more because they need straighter tracks because of Newton's Third Law. They also require more maintenance. Elon Musk has some interesting ideas and more importantly interesting inventions on the technology surrounding Fast Trains- some of these ideas have been around for many decades. But implementation of pervasive new technology is difficult. I wish Elon Musk the very best.

For many years I believed that trains were viable for intercity travel- it was hard to admit differently. There is a potential for freight to be cheaper than trucks because of the labour component- but in reality the cost/ value proposition of tracks and trains is much more than the cost of roads and trucks- maybe someone needs to do a study of the reasons for this. I suspect that the competitive nature of the trucking industry is part of the reason.