There is the Apple ecosphere and there is the 4K UHD ecosphere. That creates tension. Right now, for technical reasons, it was fairly reasonable for the 4th generation Apple TV to dispense with 4K UHD support, but that will change in the next two years. Here are my best wishes for how Apple handles the transition.
4th Generation Apple TV. Image credit: Apple
First things first. I've written previously about why I think the 4G Apple stuck with 720/1080p output. "A Theory: Why the New Apple TV Will Ship Without 4K UHD." I'll expand on that below.
The second thing to note is that there are many different ways to approach one's video entertainment infrastructure. The first one is an "Apple first" approach in which the cord cutter lives primarily on the Internet with Apple products. Apps are king. The large screen display, if there is one, is simply a display device for an Apple TV, apps like Netflix, and perhaps there's a secondary set-top box or HDMI stick.
Another approach, which many still take, is that the big screen TV exists in the conventional home theater space, driven by a DVR and, likely some secondary set-top boxes. The iPad is used with AirPlay or stand alone with apps to watch video, for example, Amazon Prime.
There are some other common practices, including high mobility, but I won't try to go into details. The point here is that while Apple likes to and can control its own OS X/iOS/tvOS/ infrastructure, there is a completely separate TV industry out there that has its own working groups, standards, manufacturers and favored technologies.
The Friction Point
What's happening during in this time of transition is that those who are Apple enthusiasts are struggling to ascertain how Apple's TV vision and their own goals all fit together. A classic example of that is the emergence technologies like High Dynamic Range (HDR) which isn't (yet) implemented by every TV manufacturer in the same way. As a mere observer, I hope that this will be resolved behind the scenes at CES in January. Also, a groundbreaking event like the new Star Wars movie could ignite a rallying around a single HDR standard, Dolby Vision. See, for example, "'Star Wars' Dolby Cinema Release Could Push Forward the New Format."
There's more. Content creators are struggling with how they marry the technical requirements of their content creation with the common delivery mechanisms. Clearly Internet TV, to succeed, has to deal with highly compressed transmissions, diluting the value of 4K content. In recognition of that, the industry has developed the UHD Blu-ray standard for several reasons: catering to purists, a recognition that many people are still collectors, and as a means to propel early content—which is always a gripe.
Here's a great article that sums up the state-of-the-art in 4K UHD TV today. "TV Insider - The industry wants you to go 4K, but the professionals won't be joining you." The title sounds dramatic, but the article itself lays out pretty much all the issues with this technology transition.
Amidst all this technology, HDR, deep color, nano-crystals, full array backlighting vs. edge LED lighting, the quality and security of smart TV OSes, Apple has to figure out how it's going to fit in. That's because Apple isn't an industry leader in the various kinds TV hardware. Apple doesn't officially attend CES, isn't a member of many TV industry standards committees, and generally tries to surprise and delight the customer with its own brand of innovation by working in secret.
After the rough spots in this 4K UHD transition are over and the technology becomes mainstream, Apple can jump in with future generations of Apple TVs that complement rather than try to displace the various supporting products people use. However, in the meantime, I would hope that Apple takes a more pragmatic approach by building products that, by their design and marketing, telegraph that Apple is aware of flux in the industry. Customers don't want to experience buyer's remorse or feel that Apple is either being callous or incoherent with its rollout strategy. Affirmations about upgradability are huge in this regard.
Here's Looking at You, Kid
The current 4G Apple TV, while very late to the game, has substantial software innovations that make viewing standard HDTV/1080p content fun. (Except for the frustrations of Siri. That's another discussion.)
From here on out, one would hope that Apple's TV product strategy and launch schedule will reflect that that their smart, enthusiastic customers want a partner (hero, actually) that gracefully contributes to the evolution from HDTV to 4K UHDTV, with all its attendant messy details. Otherwise, everything that Apple has been trying to achieve in advancing the TV state-of-the-art will just appear isolationist, arrogant and customer unfriendly.
As I recall, Apple once used a catch phrase, "Fit in and stand out." The 4G Apple TV does that now. Continuing the trend will be most welcome.