You wanna know something else? The majority of the world economy is already centrally planned. Not on the national level, on the corporate level. Business is dominated by a relatively few giant corporations with internal economies the size of some nations. None of them run free markets internally. Sears experimented with it, to their demise. Central planning is already the primary way that our economic lives are driven. It's just we let unaccountable billionaires do the planning instead of an elected body.