A lot worth considering in this analysis of why the United States' transit costs are way higher than the rest of the world:
Tunneling in any dense urban environment is an expensive proposition, but the $5 billion price tag for just the first two miles of the Second Avenue subway cannot be explained by engineering difficulties. The segment runs mainly beneath a single broad avenue, unimpeded by rivers, super-tall skyscraper foundations or other subway lines.
American taxpayers will shell out many times what their counterparts in developed cities in Europe and Asia would pay. In the case of the Second Avenue line and other new rail infrastructure in New York City, they may have to pay five times as much.
Amtrak is just as bad. Its $151 billion master plan for basic high-speed rail service in the Northeast corridor is more expensive than Japan’s planned magnetic levitating train line between Tokyo and Osaka, most of which is to be buried deep underground, with tunnels through the Japan Alps and beneath its densest cities.
There's a whole array of reasons why transit in this country is so f'ing expensive to build: an overreliance on “consultants who consultant with consultants and advisers who advise advisers," laws that emphasize cheap bids,
Culture and politics tend to form the boundaries of what we believe we can build, as well as the way to do it. Sure, economic factors play a role, but as this case demonstrates, culture forms the what and how, which can exercise a greater influence on the whole situation. That's one reason this blog exists, because perspectives that emphasize money and technology often miss this badly.
In this case, when governments in the U.S. think "we need to build a transit project," their culture jumps to "hire consultants," then to "make it pretty" before landing at "go with the lowest bid." That last one is backed up by legal guidelines that, in an attempt to curb corruption, often require the entity to go with the cheapest offer. Add all that together and you get transit that's way pricier than it has to be.
There's no iron law saying things have to work this way, just a lot of self-interested tradition, shaped by the way some political battles turned out in the past. Making transit more efficient doesn't so much require shiny breakthroughs as figuring a way to break that culture.