Maybe. On the other hand, we also barely have high-speed rail between New York and Boston or DC, and those cities (and travel between them) do drive a huge chu

Maybe. On the other hand, we also barely have high-speed rail between New York and Boston or DC, and those cities (and travel between them) do drive a huge chunk of the US economy. Chicago-Madison is interesting because they're too far apart to commute between: the drive is ~150 miles/2.5 hrs each way and train is, inexplicably, much slower. If it instead took an hour or less to get between city centers, it's suddenly doable. Similar arguments might apply to Boston-Manchester and other pairs of big-medium cities. Someone would have to run the numbers, but I think HSR has the potential to create demand, rather than just shift it from cars and planes.