The Left doesn't get many things right. Sometimes it's the complex things the Left misunderstands, for example the effects of taxation on society, the importance of free trade for growth and the effects of excess money printing by the State. But it's not only the complex things the Left doesn't understand. For example, the Left does not in any way understand that production must come before consumption.
The reason the Left is in the dark when it comes to this is that the Left is focused on the division and manipulation of present wealth, and completely ignores the fact that wealth must first be created before it can be divided.
A Leftist will often say that he wants to improve society or the lives of the poor by removing wealth from its rightful owners and hand it out to others. How does the Leftist expect wealth to be created when the creators of wealth continually get robbed? How does the Leftist think that wealth can increase when the sources of wealth are continually being drained of incentives and liberty? Clearly, none of this concerns the Leftist. He will focus on present wealth and its distribution among different groups of individuals (for example, those likely to vote for the Left), and demand that rightful owners give up their property to satisfy the grand visions of the Leftist, where nobody earns according ability, but according to whims of society-shapers.