Loewe makes TVs, but also audio systems and speakers. They have all the technology that Apple could put in one total home entertainment device: Apple TV. Maybe with (optional?) external speakers. But wirelessly connected.
The current 17" is 1920 by 1200. They're moving everything to Retina, right?
How much would a pixel-doubled 17" portable display cost? Prohibitive, I'd guess. It's almost the same resolution as a 4K TV!
Plus, as other people pointed out, the sales numbers of 17-inchers are just low, low, low.
Sure, but you don't know how Apple processes it after you upload it. Maybe they strip out the duplicate copy. Or maybe they will in the future.
What I was suggesting is what Apple might do in the future. I don't think it caches stuff now--it just downloads everything, as you say.
What is an iBook? It's just a text file with a bunch of videos, pictures, audio, and code. What does that sound like? A web page. So how do web pages handle this (or even iApps)? They download the text first, then the images, then download the video and audio only as users access it.
iBooks could use the same model. It could be a little smarter--say, download the video for the current chapter into a cache, and purge the cache 30 days after it's last accessed.