I could be wrong...it has happened before.
Maybe it's what I've seen, but the couple of times I've seen 4K it hasn't blown me away. If I look real carefully I can see the difference between it and 1080p from a BluRay disc but for general viewing...meh. The one time I saw 8K, however, I was amazed at the detail. The 4K was on screens ranging from 64 to 152 inches (including a Sony 84" LED, which I understand is a little less than 4K). The 8k was on Sharp's 85" prototype.
But the real issue, IMHO is the massive screen sizes required before the higher resolution really becomes apparent. On a 64" display (which I think is the largest "mainstream" size) the difference is really imperceptible. You do have to get up into the 80" screen sizes to get the real benefit. Most people are simply not going to have TVs that big in their living room. I think both 4K and/or 8K won't become mainstream until we have OLED screens that can be applied to a wall like wallpaper (which is years, if not decades, away). Until then, people will keep buying 1080p sets and that's all anybody will broadcast. 4K or 8K will be the enthusiasts' domain until then.
What do you think would happen if the 4K sets suddenly came down to the price of a high end LCD LED, or better yet, a high end plasma? You have to admit $22,000 for a TV is a bit ridiculous.