Buying the tech from Japan isn’t gonna solve the fact that you don’t even know how to manage a normal passenger rail line, buddy!
Also I know this is technically a Japanese news site reporting from their perspective, but the US is still seriously considering this on their end, just like how they’ve been considering it since Japan first introduced the SCMaglev prototype decades ago.
The northeast corridor is densely populated and fast trains require very straight tracks. In a place like China, eminent domain is easier and the State can expropriate land for the construction of a straight track, but in the US this is harder due to higher costs (lower economies of scale) and endless bureaucracy for infrastructure projects. So I suppose they just found it easier and a better option to build a lot underground.