TV does not offer a company like Apple much opportunity. There's no UI problem that keeps people from being able to get the most value out of their TV. People won't buy an easy to use TV at a big premium over a regular TV. This is why Apple was never going to make a TV.
The only thing people really want from their TV is cheaper, more conveniently delivered content. Apple has no TV content, and there's no way for Apple to make money offering others' TV content at a cheaper price. And there's no way to sell a new premium TV based on cheaper TV content -- the premium you gained on the TV would be more than lost on the content discount.