The original quote sounds good until you consider the effect of the velocity of money and then it falls apart pretty quickly.

Cutting taxes on anyone might be good for them, but if they don't spend it then where is the gain to the economy overall? And while the poor will spend every dime the wealthy are apt to save any excess money which is akin to a contraction in the money supply.

Taking the velocity out of the question is like taking the effect of gravity out of the theory of multiple dimensions. Take it out and the theory works, but gravity exists.

H. L. Hunt, one of the biggest Conservatives that ever lived, said money is like manure. It does no one any good unless you spread it around.