That’s only in a closed system under equilibrium, following the laws of conservation of mass and conservation of energy. To complete the metaphor, the system is neither closed or following conservation of anything. The government prints money, always expanding the total pool of “energy.” A single country’s economy is not closed, as there is trade with other countries. If we’re talking about the global economy as a closed system, it still doesn’t follow the laws of thermodynamics, due to the whole government-printing-money thing.
