[WS:] This is a semantic argument that hinges on the meaning of words rather than empirical reality. "True" socialism is no different from "true" Islam or "true" Christianity - they all are a product of human imagination and exist only in the human mind. We must, however, look what exists in material reality - which IMHO is the most fundamental principle of Marxism.
The concept of "capitalist" or "socialist" economies is an illusion created y the unit of observation - the nation state - which requires a very high level of abstraction. In reality, different arrangements exist within those nation states. These arrangements involve different property relations - individual proprietorship, various forms of collective proprietorship (e.g. partnership, cooperative, joint stock corporation), and different forms of control (e.g. market, cartel, government control).
The convergence school of political economy stipulated that any of these mechanisms can be copied and applied in different countries to achieve competitive advantage over other countries. For example, Gerschenkron argued that the Soviet system was, in fact, a result of institutional borrowing from more advanced economies (France, Germany, Japan) and thus was no more "socialist" than those economies. It was labeled "socialist" because of ideology of socialism adopted by the ruling elites, which however had more in common with peasant communalism than with the political philosophy of Marx and Engels. This ideology was basically secular ideology legitimating the whole power structure. However, calling USSR a "socialist" economy makes as much sense as calling Japan or Thailand a "Buddhist" economy.
In reality, every country is a combination of different modes of ownership and economic control - and the most interesting thing is how those modes are distributed and how that distribution correlates with other social divisions. That is where the real action is. For example, US is a socialism for the rich and capitalism for the poor, which means that economic externalities benefiting the wealthy 1% have been socialized i.e. their cost distributed on society as a whole while the benefits concentrate in a few hands, whereas externalities benefiting the remaining 99% have been not, meaning that those who are affected by those externalities have to bear their burden themselves, individually. That coincides with social divisions and deepens social fragmentation that preserves the status quo.
You can see that when you abandon the "tree-top" point of view implicit in the unit of observation being a nation state and look at national economies as a conglomeration of different modes of ownership and control. Subsuming this diversity under simple labels like "capitalism" or "socialism" is not analytically useful and can be very treacherous. As they say, an economist drowned in a creek that was on average 6 inches deep.
-- Wojtek
"An anarchist is a neoliberal without money."