Don't understand this. DPI and font sizes will be as I noted.
First, if you are running Excel models or writing in Word, it makes it very difficult to see that much data in one's peripheral vision. What happens is you have to constantly move your head left or right, but this is not as big of a problem since plenty of people have used 2x23 inch monitors. Even bigger problem is vertical screen space. You would literally need to wall mount your 48-65 inch TV so that the bottom of the TV's frame meets the desk at the lowest point. Even if you do that, a screen so large means instead of staring straight at the center of it, you will find yourself looking upwards. Over 8-10 hours of office work, this is a death sentence to your neck. Thirdly, have you tried to view fast motion 1-1.5 feet away for prolonged periods of time? There is a reason the first 5-6 rows at a movie theater are the last ones taken most of the time since a lot of people get motion sickness and headaches when the image so large Is so close. I am not sure what the scientific reason is but I can't sit 1-2 feet away in front of a 48-65 inch TV. It's not pleasant. I think a lot of people would agree. The problem becomes that as you move farther away from a large 4K TV, the larger it needs to be to resolve the extra pixels. CNET did a calculation where at something like 8-9 feet you would need a TV 84" in size to resolve 4K. That's prohibitively expensive. I think a lot of gamers using 4K TVs of 48-56 sizes confuse 4K clarity with 1080p clarity in their living room; but instead a 2015 4K TV simply has a way better IQ (contrast, black levels, colors, etc.) to their 5-8 year old LCD. That's probably where most of the wow factor comes from.
It's hard to explain until you actually use a large monitor/TV. I have a huge office desk as is and 42 is the max I would go.
Going back to my original point, a lot of PC gamers realize that if play all kinds of games but you aren't willing to keep dropping $1300 every 2 years on GPUs for 4K, might as well forget it!
I looked at so many reviews/benchmarks of 4K, my head spins and I've determined I just don't want a 27-28" 4K, 32" 4K are too expensive, 48-65" TVs are unusable for office work on an office desk, and I am not ready to buy flagship cards in pairs every gen to keep up. Once next gen games come out, suddenly Fury X CF and 980Ti SLI are too slow forcing one to turn settings down. Everyone has a different opinion but I decided to hold off on 4K. It's not ready in terms of PC monitors as most are either too small, too expensive and lack FreeSync/GSync. I just grabbed the BenQ 2560x1440 32" as a stop gap for an incredible price, which means a single flagship card will be good enough and in 3-4 years 4K will mature in all aspects from FreeSync/GSync to GPU performance. I am sure a lot of PC gamers really want a 4K screen but once the time comes to pull the trigger, all these variables I discussed become real factors in their purchase.
Like I said a single 980Ti is faster at 1440p than dual 980Ti at 4K. I would rather take 1440p @ 32-35 inch maxed out than 4K on Medium setting.
Also I really believe that games ought to become more demanding soon since we should finally start seeing 2nd and 3rd gen XB1/PS4 ports. Those games will crush modern cards at 4K considering modern GPUs barely keep up in today's games. If I had unlimited budget, yes I would get a 4K monitor and Quad Titan Xs or something.
Finally, I have a Panasonic plasma in my living room, which means even though 4K > 1080p on paper, current LCD/LED tech isn't good enough for me for the media/movie aspect of my living room space. Now if I could get an OLED TV at a decent price in 3-4 years, I might do that.
This makes 4K TV argument a bit tricky since LCD/LED tech itself can't hold a candle to Panasonic or Samsung plasma which means it fails BOTH as a media TV device and as an office productivity device. For now I am forced to have plasma for the living room and a PC monitor LCD for office work.