Continuously pumping sea water is expensive to maintain, the primary reason being marine biology. I once saw mussels grew inside a boat engine. Second reason,

Continuously pumping sea water is expensive to maintain, the primary reason being marine biology. I once saw mussels grew inside a boat engine. Second reason, land on shorelines is expensive. Many people dream about living on a seaside (except for people who did, practically speaking the idea is not that great, humidity, noise). Also many other businesses require shorelines, beaches, marinas, ports.