Another Theory

It seems that not all dogs have the same ocular equipment. And so, some dogs can enjoy TV, and others don't.

Some dogs have retinas composed of a "visual streak", which makes them good hunters with great peripheral vision, but since they have about one third of the nerve endings as other dogs, they're left with a lack of acuity.

Another sort of dog has what's referred to as an area centralis, and with this comes a denser bundle of optical nerves. These dogs have better overall vision, and are occasionally captivated by the tube.

Which kind of vision does your dog have? It seems that there is at least a loose correlation between the length of a dog's nose and the sort of eyes they have. Shorter nose dogs are more likely to have the area centralis eyes, and so would be more likely to settle down for an evening of TV viewing with their people.

...And will the cat join us? No doubt. Cats are even known to be particularly attracted to high definition TV. Just keep them just out of pawing distance...