Firstly, the attorney whose article you quote has a well known bias towards the cruise industry. And you accept his figures as fact.
He writes about Carnival cruise line, when in fact, to get anywhere near the level of profits he's speaking of he has to be talking about Carnival Corporation (owners of Carnival, Holland America, Princess, Costa, Seabourn cruise lines (and probably a couple of others I forgot to include).
The other important consideration would be to differentiate between gross profits, and net profits.
Those ships cost a half billion each to build, and they don't maintain themselves. Every 1 1/2 - 2 yrs. they go in for a scheduled dry dock, to get refreshed with new carpeting, furnishings, and mechanics.
Carnival Corp. is a publicly traded company, and those of us who are shareholders want to see them make a profit.
Do they get around the taxes by flagging their vessels outside of the US? Absolutely. Not any different from hundreds of multi-national companies who pay little or no taxes in the United States... General Motors, Apple.. for example.
The cruise lines DO bring an awful lots of dollars to the local economies whereever in every US port city they use. They also build and pay for a lot of infrastructure in ports of call throughout the Caribbean.
Their goal is to make $$, and they shouldn't be disrespected for doing so.
As to what they pay the crew. Aside from those who do in fact work for a low salary, and are reliant on gratuities, they do have a great many salaried staff on board as well. The service staff will tell you they are able to make much more working on the ships, than they would be able to do in their home countries.
If you want the crew to be paid more, you of course have to realize it would be the passengers paying that salary, either way... via salary or the presesnt system of gratuities.
At least with the present system, if you are truly unhappy with the service you're able to remove the gratuities. If they were included in the fare, you'd have already paid that money out, with no options.
While I do believe they are overdoing some of the extra charges, they ARE all optional expenses or purchases to the passenger; user pay.
I believe it's absolute fact that they are always seeking the additional revenues precisely because they have to keep their cruise fares exceptionally low to keep their ships sailing full. And, it's certainly not their fault they are doing a good job of it.
The public is gobbling this stuff up. The industry grows substantially every year. That is telling the cruise lines that what they are doing is working.
Oh.. and BTW, there is no charge for seeing the Blue Man Group on Norweigan Epic (the only ship they are on). Ya can't believe everything you read.
Without the Arison family, who started Carnival Cruise Line there might not even be a cruise industy as we know it. To that point the ships were ocean liners, used mainly for transportation, and almost exclusively for the very rich.