Dollars do not literally make the world go round. The world literally goes around because it was formed from a disc of swirling matter, and the lack of inertia and forces that would stop it.
Well, to be pedantic, there are many reasons. They range all the way from comedy, right through to just being a stickler for accuracy.
edit - looking at it again, jcd748 failed on accuracy as the earth does not lack inertia but rather possesses it in great quantities. 8.04×10^37 kg·m2, to give a rough figure.