The USA is a continental government and it doesn't have a planned economy. Most countries in the world fall into this general model, although no two are identical. There is no a priori reason the world could not be run like this. That doesn't necessarily mean it would be easy, or even desireable, though.

Planned economies are not a good idea because they don't work, and they don't work because economies are too complex for any bureaucracy to manage them, and because they ignore the desperate desire of people to better themselves, and even to take great risks to do so. Planned economies don't exploit these powerful forces so they go to waste.

However, this does not mean there should be no planning and no bureaucracy and no regulation. Those who gain a purely strategic advantage in an economy must not be allowed to unfairly use that advantage to crush their competitors by manipulating the market. This is the primary bone of contention on these boards, where this line should be drawn. Unfortunately, where we draw it must be determined and negotiated politically, continuously, there is no magic ideological formula that tells us where it should go.The opposite of tyranny need not be anarchy, and ideology has no place in sound administration.

The Cubans have a saying:

"No tan calvo que se le vean los sesos."
[Not so bald their brains are visible.]