You're assuming HSR is a "good" decision versus the alternatives, but who's to say it is?

Further down this thread is a link to this video called, "Why is China so good at building railways?"

https://www.youtube.com/watch?v=0JDoll8OEFE

The presenter and quite a few commenters seem to have a built-in bias towards rail. Don't get me wrong. I love a good train journey and prefer it to flying when it's competitive. But the video tries to be an optimistic take on what a cold eye could only describe as totally mad and dysfunctional government.

The situation according to the video can be summed up like this:

• China has built tons of high speed rail very fast, this is amazing!

• But they do it because their internal airlines suck incredibly badly.

• There are only three carriers, none of which are budget. Planes are on time only about 65% of the time, which is a staggeringly low figure. The cause is enormous congestion in the air leading to air traffic control frequently denying takeoff rights.

• This bizarre situation occurs because the Chinese Army controls almost all the airspace above China and refuses to let civilian flights anywhere except a few corridors.

• Rather than get the army under control and open up flying to competition, China decided to build tons of railways instead.

• These railways are all heavily subsidised. Theoretically some in the east are profitable, but this is more than offset by railways built along totally unviable routes. For one route the ticket sales don't even cover the cost of electricity, let alone construction debt.

• Because HSR requires long straight lines without sharp curves, HSR railway stations are often as far away from city centres as airports are (France has this problem too). That eliminates one major advantage of rail over flying.

The Chinese taxpayer is forced to pay for these economically insane projects because it's all a part of Beijing's control (or oppression) of Xinjiang and Tibet.

For vague and to me inexplicable reasons, Beijing thinks building expensive and slow railway lines between outer region cities that don't have much travel demand will somehow prevent rebellions. The logic of this is not elaborated in the video, but it's hard not to assume the railways are intended for future military use if there's a need to move lots of troops into these regions.

Now let's compare this to America, which according to Hacker News consensus is some terrible backwater in comparison.

America has perhaps the world's best domestic airline network. Competition is intense, prices are low, travel times are very low, planes travel freely in huge quantities and the airlines are (sorta) profitable without taxpayer subsidies.

America also has an extensive and heavily used railway network, but it's used for freight rather than passengers. This makes sense for all kinds of physical and economic reasons.

HSR doesn't really exist in America, but this isn't because American society is dysfunctional. It's because the massive subsidies and land clearance required are hard to justify when you have an excellent flight network, which operates just fine. Take away "suppress rebellion" and "the military causes 40% of flights to be delayed" as motivating reasons and suddenly the US decisions don't look so bad. Those checks and balances seem to be working out pretty well.