If the Soviet Union had hung on for another 20 years, it would have made it into the Internet era. A classic argument against Soviet-style communism is that central planning doesn't work. It doesn't scale. Only free markets scale.
Then came the Internet. Now, companies can scale up to planetary scale. Amazon doesn't seem to be having scaling problems - the bigger it gets, the better it works. Nor does Tencent, or Alibaba, or Citibank, or AT&T, or Disney, or Union Pacific. Competition is on the way out.
So today, central planning works at scale. No reason it couldn't work for a communist economy. China's not doing badly.