The US has a generally derogatory view towards reliance on, use of, and spending for public transit. The attitude is that Americans drive, and spending on highways or strip malls is American. Using public transit is seen as for the poor, socialist, lacking freedom, and un-American.
Also, the US car-centric identity and view/philosophy on infrastructure are not aligned with such projects. In China, a high speed rail does not need to generate profit via ticket sales to be aggressively pushed through and delivered. They just have to link the country so tertiary benefits (i.e.: new job opportunities for people living far, save time, save energy since driving long distances is a job itself, etc.) can be generated to reduce and remove externalities (i.e.: remove mobility barriers to opportunities, reduce emissions, accidents, time loss from traffic, etc.)
In the US however, it is very difficult to consider investing money (see in a derogatory light as "budgeting") into something that will not create profit. The sentiment is "we are saving some money for the underprivileged people who cannot afford cars."
China's system for government is often immediately dismissed and discredited as a dictatorship. Whether true or not, this viewpoint prevents a realistic understanding of China's system as a "rule by science." They treat development as a science and without the kind of seesaw battling on elections, policies, and negative attitude on public transit, and can develop high-speed rail and infrastructure primarily as a science to address problems of pollution and mobility. The entire HSR system there is systematized.
This is simply not possible in the US, even if that's what people want.