You’re comparing a passenger rail system to a freight rail system. Totally different beasts.
China:
Total length: 155,000 km (100,000 km electrified)
Total passenger/km: (1,470.66 billion passenger-kilometres, 2019)
Total freight: 3,018 billion cargo tonne-kilometres (2019)
US:
Total length: 257,722 km (160,141 mi) (I can't find figures on electrified length, seems at most 2000km?)
Total passenger/km: (10.3 billion, 2014)
Total freight: 1.71 trillion short ton-mile, approx 963 billion tonne-kilometres (I used wolfram alpha for that conversion)
So if my calculations are correct - which they may not be - on fewer rails China transports an order of magnitude more passenger and freight traffic.
But the premise is meaningless. It's easy for a government to affect the usage of something by subsidizing it or constraining alternatives to it, which has little to do with whether it would be more efficient or well-managed as a public agency.