I don't agree with a couple of your points like the durability and being expensive.
Tape is usually 1/3 the price of hard disks and takes up less room. Tape also has great reliabilty as it was stored in a large tape library and never moved.
Bill is on to something with long term storage needs. When people think of tape, they usually think of some small LTO system or a tape cassette. When archiving important data, larger companies used to use (Many still do) tape libraries that could store up to 900PB. These were 100% purely automated. Before that data even got to the tape, the hierarchical storage manager of the library would store the data on a cheap hard disk (Data that was not accessed for a period of time) then move it to tape storage. Once on the tape, the data can be recalled thousands and thousands of times and never be corrupted. In fact, the data on the tape was automatically tested and verified by the library that the data is good and uncorrupted...unlike the various Raid Configurations that have corrupted data on them, usually due to human error.
Now think outside the box
You say it cannot work for old archived video? Why not? If a tape library had lets say 200 to 500 tapes or many differnt tape libraries we may have something. Lets modernize it a little. Lets say we take technology, like a BitTorrent technology, and stored small bits of data everywhere (Internal Libraries). When you need the video, you could get it in seconds by using a torrent like client that pulls the data from mulitple tapes, libraries, and etc.. With a technology like this, we could also scale it down for small company storage. Our industry has a lot of innovation to seek out. We can get a lot of innovation from other industries like torrent technology and companies like Plex.
Here is what a Tape Library looks like. You can find them in Data Centers yet.
After reading the discussion about Camera Companion, it seems to me that the security industry needs to look at these types of companies more to see how they do things. Another technology to look at is Popcorn Time. The people who created it, got out of it after mainstream media picked it up (CNN and TechCrunch (how I found it)). You can find the Popcorn Time software (Player) on Github. Just read about it and look at the code instead of using it (As torrenting movies can be illegal in your country even though Popcorn Time stated that it is not illegal in the US as they found loopholes). Basically it plays movies off of Torrent streams in almost real time (According to TechCrunch who gave it a whirl) along with artwork and credits that it pulled from online databases along with Closed Captioning. That code was actually pretty innovative and could probably be used legally in an industry like ours as it is now open source. Another cool thing about Popcorn Time was the torrentor they pulled the movies from was called Yify. Google Yify. What is cool what Yify does (Outside of his illegalness if it was even illegal in whatever country he is from) was that he took BlueRay movies, around, 8 GB's, and made them into a compressed movie that was around 1.4 GB's. It is 1080 video, but like John talks about every other day, the qaulity of the pixel is lower, but does not degrade the qaulity of the movie enough to the average user. Mainly, from what I can tell, is the resolution is lower in the background scenes and more noticiable with black or gray scenes with boxing, but qaulity is still on the level of a Netflix movie. I have tried to google how he or she does it, but I cannot find out. Do they use some sort of smart compression outside the main areas as the main scene looks like great qaulity? And how do they compress so many movies in short periods of time? It takes my computer a long time & uses a lot of computer resources to compress (& change format) a movie, I own, so I can watch it on my iPad using HandBreak. Google all of this stuff, as you will see great debating about how people think how Yify does this and you will see screen shots provided to view yourself. Maybe Netflix does the same thing? Videophiles hate Yify as you will read.
Anyway, what I am getting at is the technology in the Piracy and video tech world seems to be innovative. I have heard numerous times, from the Tech World, that the porn industry is the forefront of many our our great tech innovation that we enjoy today. I could see the Digital Piracy industry being included in this tech forefront in the future.
Note - Great article on supposedly how Yify encodes, even though I do not believe that Yify uses the most common Software called Handbrake. Interesting information like below in the article though.
Lesson #3 THE BITRATE DOES NOT AUTOMATICALLY IMPLY QUALITY
Lesson #5 USE SINGLE CORE IF POSSIBLE*, USE SINGLE CORE IF BATCH PROCESSING