the problem with 4k is that there is so little content most of what you watch will end up being 1080 which means the tv will have to upconvert and interpolate the extra pixels that it still is required to fill as the tv cant change how many pixels it has. This can lead to artifacts in the normal 1080 programming. Remember images always look their very best at native resolution, so currently you will actually get a better looking picture on 99% of the available content with a 1920x1080 tv since that matches the resolution of the content which is the optimum situation for an lcd screen. OLED is way more exciting tech then 4k. I'm hoping for 60" 1920x1080 oled tv's to hit the 2000 dollar mark in the next few years. 1920x1080 on oled beats out 3840x2160 on lcd no doubt about it. It's just a shame the cheapest you can find an oled set in only 1080 res is 8000 dollars and thats only 55 inches. Probably going to be another 5 years before it even comes close to a reasonable price. Luckily I'll be enjoying my panasonic 65st60 which should easily last me a good 6-10 years if need be till oled becomes sanely priced.
The lack of content argument really needs to be put to a stop as it is quite rediculous.
1) Just about everything shot on film is archived in 4K or even 8K (iMAX footage) format. Granted, this is not the same 4K as UHD 16:9 4K (in fact it is slightly higher resolution and wider aspect ratio), but it should be fairly simple to convert and release this content once there are enough sets on the market to make it worthwhile. So that is just about everything shot before 1990, and most major productions shot afterwards.
2) In 2007 the RED camera became available and was quickly picked up by the indie community. There are tons of shorts, movies, and other media that was recorded and stored in 4K outside of mainstream content which can be rereleased in 4K. Heck, even Rooster Teeth Productions is releasing a bit of their content in 4K, and is talking about doing some form of 4K release of their shorts.
3) Many major movies made in the last 4 years were shot in 4K instead of film, and many major films today are being shot in 5K and 6K to allow for a zoom and stabilize or pan and oversampeling. These are all ready to be released in native 4K without a problem.
4) Uncompressed 1080p and 2K footage can be professionally upscaled to 4K with impressive results and detail. Sure, it will not be quite the same thing as native 4K content, but it will be a fair sight better than using the upscaler built into your future 4K TV.
5) Almost any video game made in the last 15 years on the computer can be run at 4K. Sure, the textures may be a bit lacking, but most of them will still look a lot sharper than they ever did at 1080p and lower resolutions. How many people have played older 3D console games like Mario64 on PC emulator. Most of them look and play fantastic at 1080p. Certainly a big step forward compared to their original 480i format. Also, while older desktop applications may have scaling issues with 'small' 30" monitors, a non-scaled larger monitor will give very impressive screen real estate, and not cause any grief to the user.
So what are we missing then? pretty much TV content shot on 720p or below, or on a video tape format of one type or another. All of those shows from the 1990's up until 2005 is going to have a rough time transitioning to these higher end formats... truth be told, most of them look pretty horrible even on DVD (to say nothing of HD conversions). That is 15 years worth of content that will simply not make sense to purchase at 4K. It is a lot of content to be sure... but there is still a ton more content out there that will make the transition just fine.
As for upscaling being crap... it entirely depends on who is doing it and what techniques are used. Upscaling form 480i video to 1080p was extremely difficult, because there is a ton of stuff that needs to be compensated for throughout the conversion process. This was especially true in the early days. But now even a decent TV can do that type of conversion pretty well, and professional conversions are surprisingly well done, almost always looking better (much better!) than their original counterparts. Upscaling from 1080p to UHD/4K is a much simpler conversion, and can be done very easily. Even upsaling from 720p to 4K is less difficult to do effectively than 480i to 1080p. The technology has come a long way, and continues to improve, and so it is really not a problem anymore.
As for OLED... that tech has got problems, which is exactly why it is not taking off. Don't get me wrong, I did have a chance to look at a set a few times at a local high end store, and it looks amazing when it is fresh and new! And I love phones that use various forms of the technology. But still, it is a technology that is still prone to fading and color shifting over time, and it will always be expensive to implement on larger screens. LCD tech is going to overcome their backlight and contrast issues way before OLED gets a chance to become popular, and it is still going to be cheaper. Heck, even straight LED pixels instead of OLED will probably become useful and cheap before OLED gets a chance. Until one of those high contrast technologies matures enough to implement, 4K is something that is relatively cheap and easy to do that offers real benefits for most people and most content. It is low hanging fruit ripe for the picking. So rather than complaining about an improvement, how about you embrace it and implement it, and enjoy it for what it is?
Thankfully though, 4K is the last practical resolution standard for households. There is a chance that 6K may come eventually, but it would bring marginal benefits at best over 4K. 8K is another potential standard... but for most households you would need a screen taller than your average ceiling to view such content effectively when the screen is a mere 10' away. Even for your average living room viewing distance you need at least an 80" display, and preferably somewhere along the lines of 120" to really appreciate 4K. These are large displays, and going larger becomes physically problematic in most setups. This means that in another 10 years when TV manufacturers get hungry for the next cash grab then there will be more demand for things other than resolution and screen size. I think at that point we will see a push for more bit depth, higher contrast, and (sadly?) another resurrection of 3D content... but this time I think 3D is going to be done properly (without headgear) and will have a chance to stick.