I am guilty of keeping animals in cages and aquariums also. Has Seaworld and any other company thought about how much people spend to go on animal safaris and whale watching? Why not build a huge enclosure for the whales, etc... and let them roam freely? Make the enclosures with 85-90 % of viewing space and an area where the animals can have privacy. So what if you can't see a whale flip over for a belly rub. Being able to see the whales, etc... do what they want is best.
As hobbyist we are not going to refuse to buy a fish because it doesn't jump through hoops literally. We allow our fish to do what they want in the aquariums. The fish and aquarium selling business are doing very well. PETA is extreme many times. Why do we get mad when someone keeps a tiger, lions, etc... in an apartment or in a enclosure in a backyard? You know the enclosures that only have room for a animal to jump on top of wood shelters and maybe a piece of wood suspended and pace back and forth.
aparpaima that is on here has the 50,000, 20,000 gallons and more in aquariums that most of us would love to have. The only issue for us would be the money or the space to do it. However, Seaworld and the rest have the money and the space to build the largest enclousures for their animals. Even a betta wants more room. As soon as the betta realizes it's in a decent size space, their behavior changes completely. Take the same betta and put it in a bowl or a cup it acts depressed after it's been in the larger space.
Most of the public aquariums and zoos do many many things for conservation. People are just too narrow minded to go look at what they are doing outside the park grounds. The money made in a park situation is FAR greater than the money in taking people out into the wild to see animals. It's just the way it is.
A display where the animals can't be seen some of the time is one of the worst things a park can do from a guest stand point. "Thanks for your money, but the animals can't be seen today. Come again next week." Not going to fly.
I think something you guys are missing about marine mammals is that they thive off the interaction and it's 100% their own choice to participate. They aren't doing tricks for food. They get fed no matter what. If they don't feel like doing something, they won't. It's that easy. Also, the idea of a huge enclosure and letting them roam isn't the way they work. They aren't at all like keeping fish. They need the mental stimulation, play times, interactions etc... in the wild, they do the same thing.
Refusing interaction and stimulation is more like refusing water for your fish. They need it to thive. A bored marine mammal is one that will stress itself out and get sick as a result.
Every park has financial limitations - just like a private owner. It's not like parks have a bottomless pit of money and space. They are very limited, and most do a great job and using what they have to provide great levels of care for the living collections.