No matter what gets built, it'll need upkeep as with anything. Take a bridge, for example. There's lot that can change in a bridge's lifetime: - Natural disast

No matter what gets built, it'll need upkeep as with anything. Take a bridge, for example. There's lot that can change in a bridge's lifetime: - Natural disasters can cause it to fall - Accidents can damage it - New regulations can prevent it from being used - Your government could decide to simply close it Maintaining any service for 100+ years requires humans to maintain it.