I run a NAS, in various forms, for almost 20 years. The lifetime is quite longer, I still have ~ 10 year old drives in the backup NAS built on a Ryzen 1600 (8 years) and the average power supply works for me 10-12 years. The primary NAS is still on hardware that is more than 5 years old, except the drives that I just replaced with higher capacity.
As I find the size of current drives bigger than my yearly additions (personal pictures and movies), I am quite happy with a 10 year lifetime at low usage. I would love some reliable and affordable long term offline storage, but backup tapes and a reader are not affordable and not in common use for end users. Otherwise I would build a tiered storage system with more reliability and even performance (nvme hot tier? maybe).
Wow nice! I had some HDDs , some of them were alive till 10 years but not much longer.
I'm amazed that with all these technologies we haven't figured out how to store data long term (atleast couple decades) without changing the underlying components. Like you said tape drives aren't for end users.Also with how technology is evolving (fast and disorganised) I'm not even sure if you would be able read a drive in 20 years. Very tech is that backward compatible.
The good thing is that 10 years later you need less HDDs of larger capacity to move your data to. And they tend to be cheaper. So every 10 years you move the data to a new set of disks, works good enough for most people. I did it a few weeks ago, it took ~ 8 hours over 10 Gbps Ethernet.
It is not necessarily bad we don't have a very long term storage solution. Imagine you took backups on 360kb FDD 40 years ago, you were drastically limited on how much data you could store and if we assume you had 1 GB of data back then, that is a huge pile of floppy disks to copy at very slow speed. Now imagine you have 10 TB of data today and that will be a tiny fraction of a microSD in 40 years, but reading your 10 TB from HDD will be painfully slow in the year 2065. At the same time if you replace the storage medium every 10 years you keep up better with capacity and performance.
In many cases the cheapest "offline storage" is a second NAS in a friend's or relative's apartment if your data amounts is in the multiple terabytes.
If not, Amazon Glacier is cheap-ish, as is Backblaze B2 and Hetzner storage boxes.
True offline media like tapes and DVD-RW is mostly dead nowadays as far as I can see.