well you have a very good point there especially about the "crappy print scans" and difference between blu-ray and dvd and how bigger difference it actually is in terms of "Real Size" for 4K
It's not really about what we can appreciate in terms of superior visual quality, it really is boiling down to a reality of what people can keep up with not only in terms of price but also being able to wrap their head around something as simple as aspect ratios which unfortunately most people won't and don't care to grasp so how on earth do we expect the same people today who cannot grasp aspect ratios to begin to grasp the difference between resolution.
I remember when people used to want to increase resolution even though it would mean text size would become smaller in fact so small at the expense of people not being able to read it in a larger audience at the back just because they thought higher resolution was better. (that is without knowledge of consideration of text format)
It's such a misunderstood medium to the masses and even if people are sold new "toys" they will be simply lost in a wilderness of new technology before they even properly understood the last wave of technology they experienced.
I suppose it's like buying a Ferrari Car but with a limit to how fast you can actually go (at present) unless you are using it for high end apps or gaming but perhaps not as expensive. It's all so misleading and I think most people will be disillusioned by their purchase of 4K sets at this time but many will just lay out the money without really understanding what they are buying just because they were sold it.
But if you take yourself out of the domestic market and into the commercial market look at the prices of DVI fiber or 6 core or 4 core or 2 core fibre kits over even 20 meter lengths with transmitters and receivers. It's by no means cheap and you also have HDCP shit issues that potentially need to be overcome. depending on the display and the content a scaler would perhaps be required... All in all not very user friendly, with hurdles like this even currently for 1080P HD 4K is far too premature. Oh yeah forgot to mention also what the content will be playing on and what system that would use perhaps a media server or Brightsign or watchout system now it starts to get even more expensive...