I bet you have a pretty sweet TV. It’s probably big, and bright, and connected to the internet. It plays movies and TV and streams stuff and is probably paper-thin.
And that’s the problem for TV manufacturers. Your TV is more than good enough. But they only make money when you buy a new one (unless they’re Panasonic. selling ad space on their menu screen). So imagine their desperation to get you to think your awesome TV is worth discarding in favor of a new, several-thousand-dollar model.
Manufacturers are going to have a similar uphill battle with 4K as they did with 3D. Besides the fact that people don't want to keep laying down $2K+ for a TV that does the same or similar quality to what they already have, there's also a content problem see here and here, and a delivery problem. While bigger always appears to be better, I don't think in the case of 4K TV's that it will have any impact on the viewing experience.