Without a doubt, bigger ships bring more cargo in per ship, but they also bring a decline in the local workboat industry of the ports they visit. Bigger ships decrease demand for ship assist opportunities, which means less work for tug workers. Less ships calling at a port translate into less need for bunkering vessels, fuel barges with tugs, lube oil vessels, and ships stores & supply vendors. Shoreside, the need for longshore workers decline as the size of ships increases.
The economy of scale is obviously apparent and benefits the ship operators and their customers. Does the human economy of the port suffer because of unemployment and stagnant wages due to the lessened demand. Aren't those folks part of the consumer base in the port. Lost wages mean less demand for the non-discretionary cargo delivered by the bigger ships. Less demand for non-discretionary cargo allows smaller vessels to compete against their giant sized brothers.
Where is the balance? Does anyone actually look at the total economic effect these big ships bring to a port?