Yes as far as ownership goes. but If the US tries to impose minimum wage on any ship visiting US ports, I'm saying they will just not visit US ports, they will home in the Bahamas, Bermuda, Costa Rica or the Caribbean. They would have to double the price of cruises to pay their crew $20 an hour and adhere to US labor laws. God help them if a Union got involved.
They would lose some business if people had to fly outside the US but except for the shortest cruises, it would probably cheaper to fly to another country (the price would drop dramatically) and pay a normal cruise fare then to board a cruise in a US city with severely increased fares. Many people already fly to cruise anyway. I live in the Baltimore area and have taken cruises from there but the vast majority I fly to Florida for.