This just seems like hand-wringing for the pitiful state of the rail system in the USA. A country can have many dense population centres separated by large distances, making HSR viable and worthwhile, but still have low population density overall - just like the USA. The only real obstacle is political will/public support.
Western China has around half the population density of the USA but is already served by a 1,900km HSR line.
The state of the rail system is a relatively reliable measure of how densely populated a country is.
This just seems like hand-wringing for the pitiful state of the rail system in the USA. A country can have many dense population centres separated by large distances, making HSR viable and worthwhile, but still have low population density overall - just like the USA. The only real obstacle is political will/public support.
Western China has around half the population density of the USA but is already served by a 1,900km HSR line.