I have been thinking a lot about the misunderstandings of Hayek's "The Use of Knowledge in Society" essay. Below I offer what I think is a quick summary of his argument that stresses both the importance of private property and the price system as jointly necessary for economic coordiation.
1. Knowledge IS decentralized in that each of us has our own personal knowledge of time and place (and that is often tacit).
2. Therefore, planning and control over resources SHOULD BE decentralized so that people can take advantage of those forms of knowledge.
3. HOWEVER, decentralization of control over resources (what Hayek calls "several property") is necessary BUT NOT SUFFICIENT for social coordination.
4. Effective decentralized planning also requires that people have access, in some form, to the bits of knowledge that other people have so that they can form better plans and have better feedback as to the success and failure of those plans.
5. Providing that knowledge is the primary function of the price system. Prices serve as knowledge surrogates to enable people's individual knowledge and "fields of vision" to sufficiently overlap so that our plans get COORDINATED.
6. In other words: decentralized control over resources is NECESSARY BUT NOT SUFFICIENT for a functioning economy. Such decentralization requires some process that actually ensures that separately made decisions are, to a signifcant degree, based on as much knowledge as possible so that economic coordination can be achieved. That is what the price system enables us to do. [EDIT: and the prices in question are not, and need not be, equilibrium prices.]
Decentralized decision making without a price system will produce very little coordination and prosperity. Centralized decision making will render a price system useless for economic coordination.
The fact of decentralized knowledge requires that an economy capable of producing increased prosperity for all has both decentralized decision-making (private/several property) and a price system to coordinate those decisions.