Re: Back-of-napking calculations
Most HD and virtually all UHD is compressed prior to storage and editing. There are applications where a pure feed is taken from the camera to a broadcast truck or similar via sdi but the vast majority of footage is stored in one compressed form or another. The sony f65, which sony would love to tell the world is an 8k camera (it;'s actually something like 6.5k but the pixels are rotated 45 degrees) takes a 19gbps stream and drops it down to between 1.5gbps and 5gbps. This is what is stored for editing and sony are rather high up the scale on the bitrates, their other 4k offering is 600mbps for 60p 4k raw. .
Arri make a camera called the Alexa which can record pretty much uncompressed but I haven't used it so I'm not sure if it doesn't just output that to an external recorder which then compresses it on the fly for editing. People get a little confused and assume that because it says 'RAW' it means uncompressed full bitrate. In reality even in cameras (i believe nikon does this) raw can be compressed either lossy or lossless and retain its ability to grade \ alter colour temp etc. It's highly impractical, and to some degree has been since HD was released to store raw data streams uncompressed. Even sony's $60k camera compresses the data. Depending on what software you do your post in and what camera you use you can still work realtime and if you are stuck you can often work realtime at half resolution. If you are really stuffed you can transcode it to a better codec for working but this is less common now as computers are faster, coding is better, there is often gpu support or add in cards and cameras often use a decent codec onboard anyway. AVCHD used to be a ballache, now that isn't an issue and it can be edited pretty much on the fly at full res. Studios won't be loosing much sleep over this. They will have decent arrays and a long term storage option and by the time they get sick of replacing hard drives in the array the entire film and raw footage will probably fit on 2 drives anyway.
The hobbit was a great film for seeing all that in action, they made a big deal about it being 48fps and that allowed you to see how they actually did the work. Digital, even 4k, is significantly cheaper than filmstock for purchase, use and storage. Honestly if it wasn't it wouldn't be used. Film was and is very expensive. A small event shooting company, mom and pop style, will have 250-400k sunk into cameras, glass, lighting, power, audio etc. These are the folks I tend to work with, they think nothing of shooting 2-4TB a day of 4k across 2 cams. Storage costs aren't high, maybe $300 for a couple of external drives that you need to replace every 2-4 years by which time drives will be bigger etc. They'd take between 15k and 20k for that shoot. They're good :)