So, are you saying that capitalism is the apex of social evolution? Or that it was a necessary stage on the way to a to be hoped for socialism?
[WS:] Not at all. I'd never argue an "end of history" line. I am an empirical scientist not an idealistic philosopher, my interests lie in historical contingencies, path dependencies, and scope conditions rather than constructing great but unverifiable historical schemes.
But if you rephrase your question as "are you saying that nominally capitalist countries were more efficient in production of surplus than nominally socialist ones?" - the unqualified "yes" is an obvious answer. But this is not what I argued. What I argued is that central planning (aka "Socialism") played a role similar to wheel chair - it might have not been as efficient as the modes of transport available at the time, but it was the only hope for mobility for a person with broken legs.
While we are at that, I think that the theme capitalism vs socialism is not only misinterpretation of Marx, but a gross misconception of reality, framing it in simplistic terms of biblical struggle of good and evil (for which I have utmost contempt) to avoid a difficult intellectual task of studying and understanding how economic and political institutions actually work.
Going back to the issue of efficiency in surplus production, I think it is a necessary pre-condition for creating just society and good life that Marx (and others envision). How else would the material product be created? Falling like manna from the sky? The issue is not the production of surplus but its use - for public good or private profit, if I were to simplify things. The goal of socialism, at least in my book, it the maximization of the former, which usually - but not necessarily - means imposing limits on the latter. The real question, therefore, is how to achieve that goal?
"Ownership of the means of production" was one possible answer, but by now we know that this was dud. We do not need to study the history of the Soviet development to know that, all we need to do is to look how our own publicly traded (and thus owned) corporations work. To make a long story short, dispersed ownership of the means i.e. institutions of production does not mean jack squat - it is a symbolic but otherwise meaningless participatory ritual. A CEO is nominally an employee, while grunts like us are "owners" if we bother to buy stock. What really matters is the actual control of these institutions accorded mainly by their organizational forms, operational rules, forms of authority and their perceived legitimacy.
Therefore, the main problem to solve is not how to "end exploitation once and for all" - which belongs to the good and evil genre - but how to optimize the production and distribution of surplus in an increasingly complex society. How to reconcile multiple conflicting interests and preferences? How to factor in values and goals that cannot be easily monetized? How to reconcile the quality of life with its sustainability? The so-called "revolutionary Marxism" not only failed to provide answers, but also to ask the right questions (neo-classicals at least did the latter, even if they gave simplistic and off the wall answers).
To sum thing sup, I do not believe that the problem of optimal surplus production and distribution will be solved once and for all by a millenary event called socialist revolution. It will be solved by institutional changes and reforms that may take long time, but I hope will eventually happen.
Wojtek