We must be working from different definitions of efficient.
Yes, the CCP can say jump and expect their corporations to do so, but when everyone in a modern economy jumps at the same time, massive oversupply is the result. More market-based economies are also prone to similar overproduction when everyone gets caught up in the same mania (see AI datacenters), but investors will eventually stop lighting their money on fire when it becomes clear that the returns aren't there. Chinese companies, on the other hand, will just keep jumping until the CCP decides that they are done jumping.
Our feedback loop is geared towards only doing things that provide a return on investment. Their feedback loop has things like social stability and global competitiveness as competing goals to actually doing productive work.
Yes, they are able to accomplish a tremendous amount when they set their minds to it, but doing a tremendous amount more of something than there is actual demand is waste, the opposite of efficiency.
When I say they prioritize social stability, I mean that they won't stop producing cars regardless of how little economic sense it makes because they need to keep people employed to stave of massive civil unrest. And global competitiveness counts for little when the countries they want to export to implement anti-dumping policies to protect their own industries from government-subsidized Chinese exports.
China is efficient but largely because they don't actually have to obey the State. They are capitalist; they compete in the global market and follow market signals.
The CCP does put a heavy thumb on some scales, but so does every country. Perfect efficiency is not optimal when circumstances change, so states always enforce some redundancy.
There are many differences, of course, but just don't get the idea that China consists of monopolies in a command economy. They call it "capitalism with Chinese characteristics."
