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.
https://www.federalreservehistory.org/essays/glass-steagall-....