I think the leftists for the past 60 years have acted with good intentions; they think that they have been doing the right thing(s). However, they seem to do the same thing time and time again. Namely that they pretend to know all the variables regardless of context and argue that they are able to account for all variance via central planning. That is what Hayek called "pretense of knowledge". Nassim Taleb's Black Swan talks about that in depth. The failure to account for the "emotional" variable is what this article is about!
In fact, that is the reason Econ is not a science. It is basically impossible to create rigid future-predicting economic models. Physics can do that because you can isolate and probe, while econ is far more complex of a structure where isolation of a variable is basically impossible. Even if you managed to do that it wouldn't matter because variables in aggregate tend to give rise to emergent properties.
I think of economics as an NP-complete problem (perhaps even EXP). It might be possible to create statistical models that are "good enough" in most cases. But they are not deterministic or efficient. Therefor, I don't believe that centralized planning will ever work on these large scales.