I'd disagree that the USSR was the only "legitimate" attempt. And even accepting that premise I think it does still show a flaw in the system, which is that it

I'd disagree that the USSR was the only "legitimate" attempt. And even accepting that premise I think it does still show a flaw in the system, which is that it was easily exploited by a despot to seize control. By allowing the state absolute control of the economy, which is necessary to transition into a truly socialist system, you give the people running the state immense power. Then you just have to hope they treat it responsibly, which as we know, didn't happen. I made a longer argument about that here, probably better to link it than reiterate it: https://news.ycombinator.com/item?id=16689969 https://news.ycombinator.com/item?id=16689969