I have just reviewed two depressingly bad TVs. It occurs to me that some TV makers are simply not doing the obvious thing when designing a TV: standing the near finished design beside a good TV and comparing them.
Of course, they would need to have decent test material at a wide range of resolutions and in both 50 and 60 hertz. I can help with the former. Then all they need is a HDMI splitter and a good comparison TV. I’d suggest a Pioneer Kuro.
There are some things that they won’t be able to fix at this late stage, such as getting black levels to match those of the Kuro. But they ought to be able to tweak the scaling, the deinterlacing and other aspects of video processing so that they produce a nice picture. Not the junk that so many of them are current producing.