Just because bettas in the wild can survive like that doesn't mean we can treat our pets like that. Would I keep my very active 3 yr old in a closet? NO! Why should I treat my fish that way? I would think that any sensible fish owner would provide good conditions for the living creature they provide for. In a way, the child analogy is a good one. Because you are responsible for the child or pet all their lives (just ask any parent, just because a child has grown up, does not mean they do not need/love/care for their parents.)
I did see one betta in a vase combo where the store DID take care of it properly, and it was not for sale. partial water changes, rinsing the plant, and very important, feeding the betta. The female in question looked quite happy. No signs of stress that I could see.

The major point on this is most people are not told how to properly care for them, and the plant is usually totally unsuitable for this type of set up. I keep mine in small 1 gal to 2 gal tanks, with a small java fern. They are very friendly, and appear to have a blast playing with the java fern. My female has a bad habit of jumping over a leaf that is up at the surface, so she's in a 2 gal tall tank, with 4 in of space between the secure lid and the water. As far as I can tell, she does this for fun!