There is only one country that built a high speed rail network of length and ubiquity that would meet their needs, and that is China. Even then, the country has a lot of underutilized high speed rail infrastructure and built a lot of the network for other than economic reasons.
Even if the USA was to start a massive federal level HSR program tomorrow, it would likely be several disconnected networks which may never connect across the Rockies. The city pairs just aren’t there.