However, I think there is another issue in the US: last mile transit.
Even if the US magically have the rail system similar to China today, using it in cities like Houston etc. that has poor public transit would still be a pain in the ass in practice.
It's another reason (besides density) why the Northeast Corridor works pretty well for rail. The biggest cities (Boston, NYC, Philadelphia, DC) have pretty good transit systems and the train dumps you downtown which will often be where you want to be.
Houston is arguably a particularly bad example. But there are a lot of cities where you pretty much need a car if you want to be at all mobile.
However, I think there is another issue in the US: last mile transit.
Even if the US magically have the rail system similar to China today, using it in cities like Houston etc. that has poor public transit would still be a pain in the ass in practice.