Personally, I think the main reason is money.
Cruise lines have been changing over the last many years, and not necessarily for the good. Micky was great for Carnival and wonderful for cruising. He brought the cruise industry from something 'only for rich people' to something the average person can now enjoy, especially families. At the same time, he listened to passengers and respected what they had to say. Because of this, ships began to change in design. For example, conventional wisdom was that you could not have balcony cabins on a ship - now, ships have upwards of 85% balconies. They also began to push the limits and advance the technology. Ships use to be all steel because in the past they were made for transatlantic crossings. Now the upper structures on ships are made from aluminum allowing for major changes in design.
Ships have also become huge in size because bigger allows more amenities, which attracts passengers and therefore increases profits. Smaller ships simply don't have as good a profit margin as big ships. But then passengers also have to be herded like cattle.
For the most part, all of these changes have come within the last 30 years. Now, pretty much everyone in the U.S. knows about cruising and it's become a mainstream vacation option.
So what's next?
Again, just my personal opinion, but when Micky left, the cruise industry began to change again. It began to be taken over by 'bean counters' who seem to be more interested in the bottom line than in providing a wonderful vacation experience. They seem to be constantly trying to fine-tune their product, not to service the passengers, but to save expenditures where possible while getting the most profit out of each dollar.
I don't know the exact numbers, but in the past a cabin steward would be responsible for a lot less staterooms than they do now. They were able to take their time and make sure the staterooms were perfect and the passengers were taken care of. Now, they have more staterooms to clean and it's more of a quick assembly-line style of production. Less about quality of service and more about quantity.
This holds true throughout the ship. I had a 1-1/2 hour conversation with one of the head chefs on a ship and it amazed me as to how they have changed. Where they use to cook and bake everything from scratch, now many products are brought onboard pre-prepared and ready to 'heat-n-eat'. This costs less and requires less staff, but it also has impacted the quality of the food compared to what it was like many years ago. Again, less about quality and more about quantity. Take a look at the Oasis-class ships. You simply cannot feed 7500 people (passengers and crew) within a 4 hour window for dinner and do it with a high level of quality. It has to be done with a conveyor belt production that relies on quantity. And as with most things in life, many times an increase in quantity results in a decrease in quality.
Look at McDonald's. When I worked there back in the mid-60's, we made the french fries from scratch starting with fresh potatoes at each restaurant and they were excellent because the finished product was fresh. Same for the burgers. Now, everything is prepared in a massive plant in huge machines, then frozen, and shipped out to the restaurants to remain frozen until cooked. They are no where near as good as they use to be. Yes, they're still cheap, but at the cost of quality. That's why places like Five Guys are so popular. People are willing to pay more to get better quality. It's unfortunate that for the majority, the cruise industry is following the McDonalds way of doing business more than Five Guys.
So, to get back to the question, where is all this heading?
They've tried to keep the price of cruising down to a manageable amount for the majority of Americans. In doing so, they have decreased the overall quality of cruising. Ships have become destinations in themselves in an attempt to keep the interest going.
But what's next on the horizon? There are only so many ports available in the Caribbean, so do they concentrate on building floating resorts so the ships truly do become the destination?
At the same time, do cruise lines continue to concentrate on the mass production assembly line way of taking care of passengers?
As I said in the first sentence, it's all about the money. We would be naive to think otherwise.
While some of these executives left on their own, some where 'phased out'. They may have you believe it's a way to streamline management, cut out redundancy, and save money. While it could be some or all of these, it could also be that they are choosing to go in a different direction and are making changes towards that. Obviously, I don't know the answer to the question, but I will say it'll be interesting to see where all this is heading. I just hope the changes will result in a better quality product keeping in mind that sometimes bigger is not necessarily better for the passengers.