Ports for big ships have historically been constrained by geography- ideally you need a very deep, well sheltered bay. A shore with shallow waters for hundreds

Ports for big ships have historically been constrained by geography- ideally you need a very deep, well sheltered bay. A shore with shallow waters for hundreds of feet simply make for very costly places to unload, and get treacherous in rough weather. On top of that, coastlines tend to be the most densely populated regions. Building up infrastructure for a new harbor sounds like a nightmare to get through zoning, let alone an environmental impact review.