Local regional high-speed rail could work in the US. In the North East, Texas and California. However for the most part air travel within the US is the better way to travel. The internal US air travel is massive, similar to Europe. The difference is the US has a much bigger territory with populations blobs in the North East, Texas and Cali. China and Japan just have massive populations in a small area, compare to the US. I know China and the US are about the same in terms of land area.
Even in the UK, high-speed rail isn't needed, we just need more tracks and station, and cheaper tickets. I can got from where I live in Carlisle to London in about 4 hours with stops. Between major cities in the UK we need a better road network. The way people bang on about high speed rail, it isn't that good and it is overrated in my view. Main difference is the Chinese and Japanese massively support their HS travel to make it affordable. The British government should have never ripped up the tracks in the 60-70-80, we had the best railway network in the world and the just ripped it up in favour of roads and cars, then they complain about pollution. HS2 is dumb.