This is kind of a dumb statement. Yes the US is one of the larges most populated countries and has been for a long time. Its just coping instead of actually engaging with the question about what makes railways good. The US put down lots of track in the 18-19th centuries as its industrial revolution was pre-car and its the biggest country where this happened.

If you look into detail and not just very simple 'we transport this much cargo' you see the US system has many disadvantages and is not nearly as amazing as some US people barging make it seem.

Frankly given the historical strength of railways in the US into the 20th century, the near perfect geography for rail and the lack of ports its quite embracing how little things are done with rail.