Apple's iTV panel?

For a long time, I've been wondering who's going to make 4K panel for Apple (I dont think Apple can sell anything else that "Retina TV"). Apple doesn't produce panel, it use LG, Sharp or whatever company who actually have factory able to produce panel, but which company is going to be dumb enough to sell panel to Apple that will allows Apple to compete against there own TV? The margin for producing panel for Apple must be a lot lower that actually selling it to consumer. Usually the closer you are to the customer, the higher the margin. It's not like most panel manufacturer didn't have their own brand and distribution network.

LG ans Sharp can produce panel for the MacBook, iPhone or iPad without hurting too much their revenue (or not at all), but after spending millions over millions on R&D to produce those panel, it would be stupid to give Apple the chance to get a foothold in a area where it could do the same that in the mobile market and have the lion share of the profit.

I'm wondering what are your thought on the subject?