I'm not sure what the point of this speculation is - yes, if any multinational company with billions of dollars entered a new market, then after several years and vast amounts of advertising, it would gain some reasonable share, and make money. But that's true of any such company (same with Samsung, LG, etc) or any market (TVs, cars, fridge-freezers). And it still has to be weighed up with what other things the company could do with those resources.
Yes, I'm sure that lots of people say they might think about buying some new TV, but that would be true of any smart TV. I considered buying a Samsung TV - just as I also considered a Panasonic TV, an LG TV, and so on, but ultimately I didn't buy one from Samsung or Panasonic, as I had to choose one.
I'm really not looking forward to the unfair vast amounts of media hype and free advertising they'll get if they do release one, whilst the smart TV offerings already here today (as well as platforms like Google TV) go almost entirely ignored by the press. We'll have to put up with morons saying how Apple revolutionised TV, or "popularised" smart TV (even though smart TV functionality is *standard* on all non-dirt-cheap HD TVs these days). Yet the reality for actual smart TV owners like myself will be that even if the likes of LG and Samsung remain more popular, we'll no longer be able to get online support for our TVs, because they'll only cater for the minority of Apple users. (Even now in phones, with Android at 75%, and iphone never having been number one or anywhere near it, I still see plenty of companies only advertising apps for the minority of iphone users - in 2005, you could get apps that worked on any phone.)
Jobs is dead - please dear media, stop hyping what just one company does.