Sorry for you guys and gals that have a 4K TV. I understand your frustration. Of course you want the new Apple TV to support 4K. The unfortunate reality though is that in the United States, less than 1% of household TVs are 4K. (Just for reference, the world-leader in 4K TV adoption is Japan which currently sits at 7.3%.) Now, couple these statistics with the fact that the vast majority of homes are not equipped with the bandwidth or data allowances to support 4K streaming, and it's pretty easy to see why Apple did not include the ability to support 4K in this version.
Don't get me wrong. I know and understand why you early 4K adopters are clamoring for 4K support. It's just that we're not quite there, yet.