The first thing I hear from any ex-Soviet who grew up in the USSR is how their lives were impacted by the constant shortages and censorship of issues with the supply chain. There's a classic joke from the USSR that goes:
"Comrade, aren't you excited for when the USA finally falls?"
"No, who will we buy our grain from?"
Another one:
"Isn't it true that the USA is rotting from within?"
"Yes, but what a smell!"
Millions of people in the USSR starved to death, and their consumer tech was among the most unreliable and poorly-made available internationally. This despite Soviet mathematicians and engineers being among the finest and hardest-working on the planet. They could only just overcome the constraints that the centrally-governed economy placed on them. The only notable exception is military hardware, which was actually funded.
What do you mean "it's obviously not true [that the Soviet economy didn't work]"?