Why can planned and market economy not coexist? Some sectors of the economy are or have been state planned in most countries. Come to think of it, in a slightly more complicated planning model, the cost and benefit of nationalising or privatising certain industries could also be included.
If you're really centrally planning the economy, then all of the decisions are made by a central authority. There's no room for anyone else to do anything, because it messes with the program. The central plan can only work of it knows everything relevant.
If you're running a mixed economy, where some sectors are planned and some are not, thats fine... but it's also not what the post is taking about.
Sure they coexist now, because, as sibling commenter pointed out, while outside of corporations market forces exist, every corporation or government entity itself is a separate world, where most of free market rules do not apply. Most of them are centrally planned in one way or another
Ok, I think we need to define what "central planning" means for people who are going to choose to participate in this discussion.
"Central planning" means "the government (or some other single entity, but usually the government) makes all of the decisions in the economy."
Corporations, despite being "centralized," and despite engaging in "planning," do not meet the definition of what we're talking about when we say "central planning." They emerge in a free market economy in order to reduce the transaction costs that would come with trying to coordinate mulitiple people as independent participants to do some specific activity. They do not exist to decide for the entire country exactly what everyone will be doing all the time to meet the entire nation's needs. That's a very big difference.
