Re: Waste of time and money, you can't break the rules of biology.
Quite right. For those who care, the angular resolution of the human eye is about 1 arcminute. This means that you won't be able to distinguish individual pixels smaller than 1mm at around 3 metres, which is a reasonable estimate for the viewing distance to most TVs in living rooms.
Assume you have a 50" TV, that is the diagonal size, which translates to a screen width of around 1100 mm in a standard 16:9 layout. In standard 1080p HD (1960 x 1080 px), that makes each pixel 0.56mm.
So, unless you have a massive TV (and in my mind, 50" is excessive), or you sit so close to it you can't see the whole thing in one go, it's going to make no difference to you whether it's in 720p, or ultra-super-mega 16K HD.
Add to that that the portion of the human eye that can actually resolve anything down to that kind of angular resolution is tiny (the fovea) and covers only the central ten degrees or so of your vision, and that everything else is essentially interpolated by your brain from shapes, colours and motion.
I've said all this before, and been voted down before for saying it, presumably by those desperately trying to justify the expense they've just shelled out for a new TV they didn't really need, and from those who sold it to them.