[WS:] Here is the prima facie evidence why the socialist thought is confined to esoteric circles of the academe - it take considerable effort to merely explain whet the quoted passage actually means, let alone to assess its empirical validity.
Most people I met ask me a simple question; "Socialism was tried and failed, so what do you see in it?" If I bother to answer (i.e. when I sense that my interlocutor genuinely wants to know instead of throwing back propaganda talking points at me) I point out to the historical context in which socialism developed, and how it was effective in addressing those specific historical circumstances (i.e. economic development independent of imperial hegemony of Great Britain and the US). If I make a good argument and my interlocutor actually buys it, it typically leads to another question "Ok socialism might have been effective in lifting backward rural societies to modernity, but what dioes it have to offer to a complex modern economy and society? Is in quite naive to imagine that collective ownership of the means of production will solve all societal problems from crime to pollution to wasteful use of resource and environmental degradation to social alienation, international conflicts and so on?"
Indeed, it is quite naive to imagine that, especially that effects produced by collective ownership did produce were quite similar to those produced by private ownership - wastefulness, environmental degradation, social alienation, crime & delinquency etc. Which seems to suggest that ownership did not matter that much after all.
The 20th century socialism was a product of the same mind set that brought us capitalism - a belief that economy can re-shape social relations at will and ultimately manufacture a better society. This had a paradoxical effect of 20th century socialism taking the "social" out of society and replacing it with "economic manipulation and engineering." That is perhaps why it fell behind capitalism - theyy competed in the same game - manufacturing a better social machine - and capitalism came with a superior product.
If socialism is to regain any relevance in a complex modern society, it must do what capitalism cannot - namely bring back the "social" to society. That means advocating social relations that make a good life for everyone instead of manufacturing more stuff. This means that the focus on economics that has dominated the socialism (especially marxist) thought should be put to a rest in a museum and a new focus on social relations must be developed.
This also means that the main distinguishing feature between socialist and capitalist thought is not any particular methodology, theory, ideology or even a political system - but the ultimate goal of the intellectual and practical pursuits - "how to make everyone live a better life" instead of "how to make everyone a more efficient producer of stuff." In intellectual terms this means reliance on a wide range of scientific research; from the humanities to social and cognitive sciences, to medicine and engineering to search for empirical clues to attain the ultimate goal. In normative terms, it means the acceptance of any value system that promotes responsibility toward fellow inhabitants of this planet (regardless of whether its fundamental premise is a belief in the supernatural of one sort or another or purely materialistic) . In practical terms, it means the promotion of social relations and political systems that facilitate the attainment of a better life by people directly involved in them while refraining from making it worse for everyone else. An economic system that is based on a full cost/benefit analysis - including above all social costs and benefits - instead of one emphasizing "efficiency" by cost externalization.
It sound awfully general, but I do not think that narrowing socialism to any particular methodology or ideology is the way to go. There are many roads leading to the same destination. To explain what socialism is one needs only to describe its goal and the principles in evaluating and selecting the means to attain that goal - and contrast them to the other alternative i.e. business dictatorship.
Wojtek