I think it's the terrible breeding, but alot of pet store Oscars dont get that big. Now with that being said if I feel my fish need bigger I get bigger. If you don't have the room or means then it would be better to get a more appropriate sized fish.
I had a pet store O at 12" std and I've had another at 14". 14" is 5-6ft tank status imo.
Lots of things are possible, doesn't mean they're right.
I could lock you in a 10'x7'bathroom to live for the rest of your life and get you to survive another 20-50 years.
Is it a good existence?
just my opinion, like them with a tall tank, they seem to like working the depth, and i can stand and look at them face to face with that wall of water. Also the larger water volume is great for keeping perams down.
I think it is a matter of opinion on this. I would say yes. But as can be seen in this post as well as another recent post many think no and that 100+ is better.