SU was economically unviable long before Chernobyl disaster. It was so mismanaged it had large-scale famines, for God's sake.
And in the USSRs case, it was from an ecomony that had just had gotten into large scale industrial production, after having been way behind under the Czars, and after a major war, a revolution, and several years of civil war.
If anything, they did better than expected. Even more so given that they had an inexperienced government, external pressure from unfriendly western countries, and had to prepare for future wars that were already breeding (and luckily the did it just in time for WWII).
The US had millions of hungry people. At the peak of the Great Depression, deaths from starvation peaked at a (still terrible) ~110k. Under Soviet rule, an order of magnitude more, actually millions, perished unnecessarily from hunger just in Ukraine.
https://courses.lumenlearning.com/suny-ushistory2os2xmaster/...
However they did fuckup in many areas in the economy, something that was recognised internally at least by some - as seen by multiple attempts at reforms.
Also, one can't discount the unbelievably favourable position of the USA at the end of WW2 when analysing this (in comparison, Soviets started with a worse position than many would believe, because Imperial Russia really wasn't well off)
It's not just the man or woman at the top who make the country work. Peter the Great and Catherine the Great tried to modernize. But the nobility put up a lot of resistance or simply didn't turn up for committee meetings.
The pre-soviet famines were of natural causes - crop failures due to droughts etc. After soviets took over the country, these were still ocurring, but were dwarfed by man-made famines, caused by idiotic economic policies (mainly by forced collectivization, which decimated productivity).
It's just that usually in such comparisons you get to see USA, and USA was an extreme outlier that makes comparison useless in my opinion.
https://www.theguardian.com/books/2021/apr/06/stalins-war-by...