This isn't entirely correct. Your example refers to two demand-supply pairs, but your analysis equates them. Consumers demanding restaurant meals, and the suppl

This isn't entirely correct. Your example refers to two demand-supply pairs, but your analysis equates them. Consumers demanding restaurant meals, and the supply of those meals constitute one pair. Restaurants themselves demanding workers, and workers being reluctant to work for current prices constitute a second demand-supply pair. For the first pair, since the change in the supply (a shift of the curve itself, not a walk along the curve) of restaurant meals is negligible except in the case of restaurants closing in aggregate, a left and downward shift of the demand curve (as you note) has the net effect of downward pressure on both prices paid and quantities supplied of meals. The second pair's supply curve itself shifts left and upward (not downward), which results in a net effect of increasing the prices (wages) of restaurant labor, and decreasing the quantity supplied (number of workers). A similar analysis could be performed from the new state of each pair: the first pair might actually see its supply curve shift left and upward due to these dynamics (restaurants may close in aggregate), causing the quantity of meals supplied to decrease further and prices of meals to rise, possibly though not necessarily up to the level they were before. For the second pair, demand for workers might increase in aggregate, resulting in a right and upward shift in the demand curve, which would further ratchet wages upward (barring another supply curve shift) and would help increase the number of workers to a level closer to what it was before any of these shifts took place.