For all its horrors and atrocities, the Soviet economy grew, and worked. Oh, not very well. But better than 0% growth. In 1910 the average Russian was an illiterate peasant. In 1980 the average Russian was a literate urban dweller with electricity and indoor toilets on their floor with twice the life expectancy of their great-grandparents.
This is, again, not intended as a defence of that monstrous system. It can be condemned on purely moral grounds alone, in my opinion. And it was not as efficient by most analyses, either. Still, I bring it up because, as a counter-example, it complicates both of the commonly made assertions mentioned in the article: that poverty hasn't decreased in any meaningful sense, and that the capitalist system is the only means of greater than 0% growth in material production.