Very smart way to look at this whole Samsung/Apple fight. I don't know of course if this is the case, but indeed the time Apple is taking to pull out the iTV is way too long, in my view, and, possibly, the reason is what you suspect.

iTV is a instant winner, in my view - and I say this knowing that, as it usually happens to me with most Apple products, I would personally probably end up disliking them -. But I think they would sell millions, just for the fact that a TV sits in your living room and look, style, and status sybolism all play such an important role there. And, come on, apps on your TV, browsing the internet, the huge eco system, controlling the thing with your iPhone (I mean, even the remote control would turn into an attractive piece of technology)... Who would not like that?!
There would still be a small % of people like me who would prefer a HTPC in the living room, but, leaving us aside, if Apple released a range of iTVs in the Fall, they'd sell millions all over the world by Xmas time. I've been expecting to see the iTV since always. It seems to me a no brainer choice. And yet...

Of course, I may be wrong, but I think your idea very well would explain why there's no Apple 46" thing hanging on people's living rooms yet.

And actually, after using Windows 8 on my HTPC for a while, Metro/Modern/Whatever UI is so absolutely good there, that I can't believe Apple is waiting for MS to take that market by leveraging the XBox + smartglass as a strategic advantage.