That, and France also has an economy.

They have nukes.

they should be built/deployed at a capacity as its needed in order of minimizing waste

Building at capacity might not be the most efficient solution. First, towns grow. Second, China keeps costs down by standardisation (the Chinese HSR system has, if I remember correctly, 3 models of trains and two standards of track). And third, China is vulnerable to earthquakes and floods. So having alternative routes is useful.

This chart is a good example of what happens when transport infrastructure is judged through a purely economic lens versus what happens when affordable travel is seen as a necessary feature of a civilised society. (Not to mention the jobs created and the carbon saved.)