Netflix doesn't really care about real resolution (image information), as long as they can count 4k pixels.
After they compress the shit out of it for delivery, it doesn't mater anyway, since everything that might have bin there, goes out of the window anyway.
I mean - 16-18 mbit for 4K? - seriously?
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If one is going to comment on Netflix, one must think like Netflix. Netflix does not live in the here and now. They live in the future. Everything in their production and delivery specifications is designed to not only create inventory of material that has its maximum future value, but to archive it in a way that is impervious to format obsolescence. What they are doing now is limited by currently available bandwidth and technology. That will ultimately be replaced by larger bandwidth and better technology, and Netflix knows it. They are trying to create product that, at least technically, will last for a long period of time. Today's shortcomings won't be tomorrow's. Like a certain camera company we know, they are thinking far ahead of virtually everyone else and doing something about it. So if you're judging them on what they do now, you're missing the larger point.