In grad school, my Comparative Economic Systems prof spent 2 years in the USSR studying their system. Two examples illustrate some of the problems with a planned economy.
1. He became good friends with the person in charge of the Trans Siberian Railway. He was coming to the end of a (at the time) 5 Year Plan time period. He was millions of metric ton miles short of his quota, which means an all-expense paid one-way trip to Siberia. So, he loaded up 80 gondola cars with rocks and ran the trains back-and-forth between Moscow and Vladivostok until he met the quota.
2. Most farmers worked on collective farms, but later in the regime, they allowed the farmers to have about two acres (dacha??) to grow what they wanted and they could sell what they didn’t consume. Those small plots produced about 2/3’s of what the Russian families ate.
The message is clear: Free markets provide what people want, not some bureaucrat. If you like the way your license branch is run, you’re gonna love Socialism.
Those aren’t just the problems of a planned economy, those are the problems of a planned economy run by psychopathic murderers.