An economy is much better compared to a machine in operation than a static construction such as a bridge.
Or compare it to the marchers who have to adjust to the changing terrain in that scenario.
Economies are affected by all sorts of obstacles: droughts, fertility cycles, disease, weather and more.
It must adjust, or face a worse fate than if it had.
The best decision makers for these adjustments are the myriad folks with their boots on the ground.
When central command is from afar, marchers may not adjust as adroitly.
This marching community may sing the same song and walk in cadence when times are easy,
and move to a different tune when it is not.
Perhaps, though in my army breaking ranks over a bridge analogy, neither the bridge nor the army represent the economy. Economy is the interaction between the two. The army does not act on economy, it is a part of it.
If we choose your analogy, tossing out the bridge & picking up obstacles & terrain, we can no longe address MoonShadow's "oscillations," but since they flopped as a Libertarian illustration, i guess it's time to march off to greener pastures, over hill, over dale & other nasty terrain.
In your model, were the "central command" represents [Booo! Statist!] oversight, think it through. The generals don't tell enlisted men how to march -- they lay out the grand plans for troop movement, so that the army doesn't march off in five different directions to fight 5 enemies of their choosing. At some lower level of decision making, another bureaucrat looks at terrain maps & aerial photos, making sure soldiers don't need to march through oceans, or lava pits with no health packs in sight if we're playing *that*. When it comes to picking up your feet to step over dead bodies, have no fear -- you'll still get to do that on your own