"... 5. Why 4K?
Ah, now this is an interesting question. It's clear many seem to think TV manufacturers are some sort of altruistic entities that only do new things if there's a benefit to the consumer. How adorable, but no. Ultra HD isn't the "new technology" it appears. Modern TVs are made from huge sheets of "motherglass." From this big piece, companies slice up smaller pieces to make televisions. It's easier (read: cheaper) to make a big piece and cut it into smaller TVs.
Originally this was in case there was a problem with part of the glass, the rest could still be sold as TVs. When you read about "yields" as part of TV manufacturing, this is largely what they're talking about.
But manufacturing has gotten really good, so most of these pieces of motherglass are fully used. Instead of slicing up one piece of motherglass into four 42-inch 1080p LCDs, what if you just kept the whole thing as one piece? What would you have? You'd have an 84-inch TV. Use the exact same (or similar) drive elements/electronics and all the various bits, and you've got a 3,840x2,160-pixel, 84-inch UHD TV. Hey, wait.
You see, TV companies are pushing 4K because they can. It's easy, or at least easier than improving the more important aspects of picture quality (like contrast ratio, color accuracy, motion blur, compression artifacts, and so on).
6. 4K is easy to market
OK, so 4K is easier to manufacturer than an actual new technology (OLED), but there's more to it than that. Ultra HD is an easy sell. It's a number, greater than another number; therefore it's "better." In the confusing world of televisions, simplifying "superiority" down to a single number is marketing gold...."