They, like HD displays, have been adjusted to appear better than they are. Lots of sharpness, the blues and contrast will be cranked up, and other detail enhancing features will be ramped up. All to make them say “hey, look at the detail”. In a shop, all the screens are competing. In your house, they shouldn’t be.
I spent ages calibrating my HD TV when I got it. I had to do a lot of simple stuff like turning sharpness right down (that invents image data, and can enhance compression artefacts), altering the white and black points, ensuring a smooth grey scale with as little banding as possible, and even using filters to ensure that individual colours were as close to expected transmission norms as possible. I’ve a BluRay disk for that, and it does take some time, but well worth putting in the time. The end result (After I had corrected some shadow clipping - blacks in video can be hard to get right) is a picture that should be as close to those used in production as possible, and I’m happy with the picture I’m getting from it. If you are using any TV out of the box without calibrating, then you are doing it wrong, and you are not getting the best picture the display is capable of.