Restructuring against a war with America scenario?
The only scenario for more than a million man Army would be India.
I had always thought of China’s large army as being primarily focused on covering its long land border with the Soviet Union/Russia. The Himalayas are an effective land barrier between China and India.
The problem with the war with India scenario has always been the exceptional risk to China and the cost of winning such a war. What possible long-lasting benefit would it gain from occupying such a populous and poor country (especially if it was also heavily devastated by a major war)?
Both sides have nuclear weapons and indigenously-developed missile delivery systems. Both sides have large, well equipped and well trained armed forces. Both sides have experienced and well trained professional officer corps.
All of which makes the current probing and poking by the Chinese along the line of control in the far north of India look pretty damn stupid.