Earlier quoted context omitted.
It's more inefficient than Capitalism, which is its Achilles heel. Socialism works when there is 'free' production to fuel it. Like in the Netherlands. It fails when the money stops pumping in, like Venezuela. Automation may provide the free input that makes a more humane (more Socialist) system work for everybody?
There is no such thing as free production because resources are not unlimited.
We still need a way to allocate the limited resources, but the primary way to do can't be labor/salaries anymore - because in the near future, unlike all the past millenia, labor of most people is simply not needed for optimum production.