The fact that companies do not operate internal markets is well known in economics. The theory is that there is a balance point between the scale at which activities are most efficient operating on a command model and the scale at which activities are most efficicently managed by market mechanisms. The position of the balance point is different from industry to industry, and also varies over time with economic conditions. Idealy you want efficient markets, but also a dynamically responding corporate world that can freely consolidate, diversify, merge, etc to adapt it's structure to whatever is most efficient as technology, supply, demand, etc shift in the economy.

This is why command economies tend to be less efficient, because any given market and corporate structure is only most efficient for very specific economic conditions. Heavy regulation of companies, markets and things like employment law tends to freeze their structure in place, so they are unable to adapt as conditions change.

So markets are only one aspect of an efficient economy. A flexible corporate, finance and employment environment is the other. Hence the economic flexibility and strength of the USA. Something as a Brit I'm perfectly willing to admit to. I'm not saying economic strength is the be-all and end-all of civil society. I firmly believe regulation plays an important part in ensuring markets are fair and laws are equitable, but all these things are not mutualy exclusive.