Building the ship is one cost - operating another. Before they ever set sail they have to hire a crew of at least 1000, train them, provide all of the uniforms, hire entertainers, design new shows, build sets, pay for home port costs, have the first 30 days of fuel and food costs, hire shore side staff to include executive staff for cruise operations... and the list goes on. The first operating year will probably be a loss so they need a lot of startup cash before the paid cruise fares start coming in to cover follow on cruises expenses.