sizzling :
Not completely true. Yes this can be the case with the entry to mid range 4k TV's but some mid range and most higher end 4k TV's of recent models shouldn't suffer. I have the 55B7V and it is just superb at all resolutions I have thrown at it putting my old 1080p to shame.
It's even more true with today's TVs regarding mainstream models that the vast majority of people can afford. The TV industry is falling apart basically. Panasonic went into financial trouble and had to sell in select sizes and select countries using LG panels, and even LG's own TVs, like the 6300, have issues with build quality and the motion control feature not working.
The fact that you give an example of an OLED model that costs over 1300 pounds ($1619 in USD) even on Black Friday kinda proves my point, and OLED btw is no winner either. You get a great picture when they're new, but they're all susceptible to burn in, and their blue pixels only have an expected lifespan of 20,000 hrs due to deterioration. That's 1/3 the life of the average LCD screen. When they deteriorate the screen gets darker, and OLEDs lack brightness compared to other tech to begin with. You couldn't have demonstrated more with you post that they are turning the TV industry into a rich man's game, where it's all about expensive, disposable TVs anymore.
Regarding 4K, the only reason 4K TVs are selling so well is because the manufacturers are forcing them on the public, they have no other choices anymore in new TVs.
LG and Samsung are the worst offenders at the demise of the TV industry. They are the ones only putting quality into their ultra expensive models. They are both known for producing flimsy models that can suffer shattered screens even when transported with no damage to the outside box. They are built and packed horribly. Just look at customer reviews of the LG 6300 models. The 6300s are also being sold as 4K TVs, when in fact they use RGBW color format, which uses a white pixel every 4th one, so technically it's only 3K. This is the kind of deception LG has been using for many years, as well as panel lotteries. Meaning they've also been known to have a mixed bag of IPS and VA panels on prior models that were supposed to be IPS.
Well before OLED even became popular among the rich, LG said on Celebrity Apprentice on a task they oversaw for an ad competition for their large screen TVs that their demographic was customers whom make $74,000 a year or more. LG built it's empire on the poor with affordable products, and now all they do is take a crap on them with shoddy build quality and horrible customer service.
But to respond to your point, yes, OLEDs don't have motion problems like LCDs, but they have other problems that make them equally undesirable, if not more so.