Innovation, Competition, Global Economic Conditions and Profits drive the Industry. I agree with Chris at Cleveland 5-6 years if it even survives.
Just think what happened to Sharp investing five billion dollars to build a state of the art 10G LCD/Solar Plant to manufacturer monster panels and prices dropped to equal losses and sent them a hair within bankruptcy and they had to convert their other plants from TV's to portable devices where they make more Profit as they provide Apple glass for their devices and partnered within Foxconn.
I believe LG would abandon OLED before they'd ever sell that size for $3K - have you ever noticed that Sony, Samsung with every passing year teases consumer with just enough features to keep flagship pricing at a standard range that never gets down to that $3K region for Flagship products. The stepchild average panels drop but the flagships remain year after year until they are being cleared for next gen with a teaser to keep it's price standard, it's no accident.
What's troubling is Samsung actually increasing the price for their flagships YOY for QDot which actually is designed to save them costs but they have such huge market share that they seem to think they can get $10K> for a 78" and that price scenario is not likely to last as they'll never garner volume sales on those as there are only so many STUPID Rich People that Sprint depicts.
Don't hold your breath for a monster size OLED to drop to $3K anytime soon when Samsung is asking about $13K UPP for their 78" QDot SUHD.
On second thought, the only way I see a drop to OP levels is if China reverse engineers/pirates and produces it with it's Communist Slave Labor - Yes then we could have them if China replicates it in the marketplace having the R&D subsidized by others upfront.