Why isn't more being done to reduce transit construction costs in the United States?

Alex Tabarrok follows on a slide deck by Alon Levy [pdf] to examine possible answers to a big question facing transit planners and engineers: Why don't we know more about why transit investments cost so much in the United States?
Tabarrok voices skepticism about one point raised specifically by Levy—that "GDP per capita is not a big factor once differences in type of subways are accounted for…"—but doesn't elaborate on that skepticism.
Here is Tabarrok's key series of questions, which also happens to be extremely relevant for the Planetizen audience (which includes both planning researchers and professional practitioners): "…isn’t it weird that a Patreon supported blogger has done the best work on comparative construction costs mostly using data from newspapers and trade publications? New York plans to spend billions on railway and subway expansion. If better research could cut construction costs by 1%, it would be worth spending tens of millions on that research. So why doesn’t the MTA embed accountants with every major project in the world and get to the bottom of this cost disease?
FULL STORY: Why Don’t We Know More About the Subway Cost Disease?

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