Except the RAID concept can be extended much further. If you have a file that takes up 8 drives worth of space, you can store it on 16 different drives such that you can lose any 8 of them and still recover the file (or perhaps it is 7). So only twice the space to be able to withstand a major loss, an extremely unlikely loss if the 8 drives are at 8 different facilities.

However, as soon as you lose 9 drives you have lost *everything* which is the downside. (Same for Raid 5. You can lose 1 drive OK, but 2 drives and all your data is gone, which is why people go to RAID 6 for large arrays, where you can lose 2 drives, and 3 takes you out.)

Yes, I understand you want to store all the extra footage. So increase the size tenfold. It's still no $12,000 per year.