The problems with getting public infrastructure projects done in time or at all are political, not technical.

There typically are no technical solutions to rhose.

AGI is easier than getting New York City to complete an infrastructure project in less than a decade or less than a billion dollars.

The corruption and graft run so deep you would have to literally murder a lot of people to get that to happen.

That is true. In fact it relates to one of current America's greatest truths: coordination problems here are much more difficult than many technological problems. This is what makes many of those "oh so you take those autonomous vehicles, put them on a track for efficiency reasons, then link them together so they can transport more people, and voila! you have a train!" comments ring hollow.

Building a train requires coordination. Building an autonomous vehicle requires technological innovation and convincing a few people at the top levels of government. The specifics matter (and the Abundance guys have done a great job summarizing them) but it's due to an entrenchment of certain styles of laws.

So the answer to "why do Americans build self-driving cars to ease transport when Europeans just built subway systems?" is "we do these things not because they are hard, but because they're actually much easier than the other thing you find easy".

The "problem" here isn't the construction of a tunnel. It's the political reality of the people on top of it.

You have to deal with directly affecting real estate owners, potentially 100s of thousands of different ones in NYC. Not to mention 100s of years of underground infra and all the different companies that own that stuff without cutting service to anyone. It's insanely difficult and I'm not sure I understand why you think it wouldn't be.

Haha the technical difficulty is not the hold up here sweet summer child