It's not so much that third party manufacturers will cherry-pick (that implies they're willing to have panels they discard or use elsewhere), but that they are customers of LG Display. As customers they are then able to demand certain standards of quality/spec/tolerance are met for the products they buy. This might be different from one to the next e.g. Sony might demand a certain efficiency/brightness spec where Panasonic might demand a tighter colour uniformity. Point being, they can set different requirements than LG.
The flipside is, they are paying more per panel because a) they demand these standards and b) they are a customer, not a partner inside the same parent company. That's (one of the reasons) why Sony et al will charge more than LG for a device using the same panel.
slight nitpicking atmittedly but I believe LG (tv) is still a customer of LG Displays, it wont make any difference that they have the same parent company.
As you righty suggested, its about the tolerances etc that each customer requests - Sony and Panasonic have to have as many "differentiators" from each other as well as from LG TV option for the public
The separate question is whether the fact that LG (tv) is buying enough panels in total to get a better price than Sony/Panasonic due to the significant number of "worse" panels that are within LG (tv) 's agreed tolerance's but outside the other two (probably one major reason why LG have 4 or 5 models for every generation where Sony and Pana usually have one or two).
Yeah I agree but why should Sony or an partner or customer have to pay extra to get a good quality working product that already cost thousands of pounds?
To me this tells me the Quality Control standards are either set that low or don't exist or the QC team are not doing their job properly.
Its been mentioned before also that people would pay for a QC test before delivery, that way they get a product free from banding and uniformity problems, dead pixels etc, I get that but really if the job was done properly in the first place we wouldn't be seeing people having to diagnose and QC check their products after delivery and its reached that point a long time ago.
There is a guy over on AVF who bought the LG G1 77", 3.5K TV he got sent 4 panels, all of them terrible uniformity and banding, lucky it was Mr Richer and they exchanged it each time and apologised they could see it was unacceptable image quality for such an high end spec TV. In the end the poor guy just got a refund after 6 months and went projector route.
It almost feels like that QC Passed sticker has very little meaning left.