So lets break this down.
4k resolution - whilst owning one would be cool, 99% of your content would be lower resolution, with an awful lot of it (mainly older films and tv shows) not even being full hd.
Siri - I cant see how this is really a killer feature for anything. It's voice control hooked into a search api. Nothing fancy really, and the only part that would be of any use on a TV is the voice control part...but even then will still be a lot more hassle than using a remote.
Integrated cable box so a lump of plastic to put cables in? Seriously?
HDMI & Thunderbolt/Lightning/USB
Thunderbolt would have no use on a TV. It's meant for high speed transfers and such. You wouldn't be doing that with a TV. The most you'd use it for is to plug in an external HDD, at which point you eliminate the point of having all this stuff built into the TV instead of as a set top box. Lightning would be pointless, but USB may be useful for some.
a la carte shows or channels controlled via iTunes If this happens, it isnt something that could be done quickly. I'm not talking months, I'm talking YEARS. The licensing restrictions around Tv shows and movies is insane, and theres no way Apple would be granted any sort of global channel license in a flash.
So at this point you're happy to pay $5k for what is essentially exactly the same as the current AppleTV, but with a fancy screen. $5k for a screen. That's the only part of your list that cant be implemented into the existing AppleTV.
I know 4K is what' being promoted, but there isn't any 4K content, it's all a bunch of BS right now. People still mostly watching 720p with Dolby Digital believe it or not.