Communism works, it's just human failures?
The measure of whether something works is whether it prevents human failure.
https://www.federalreservehistory.org/essays/glass-steagall-....
Banks in other countries were affected too, despite regulations.
Regulation works but it was just human failure:
https://en.wikipedia.org/wiki/MF_Global
However, socialism is not communism, which is what the GP comment mentioned.
Communism works, it's just human failures?
The measure of whether something works is whether it prevents human failure.