One option that hasn't been mentioned is tape archives. It's not for everyone, but tapes (LTO) do have a lot of technology and infrastructure behind them that is built for longevity.
In particular, you can do cost-efficient archives to multiple tapes and store them in safe locations. If (and that's a big if) the base cost of the drive is tolerable.
There was recently a wonderful post and discussion on LTO for "normal" nerds [1].
One option that hasn't been mentioned is tape archives. It's not for everyone, but tapes (LTO) do have a lot of technology and infrastructure behind them that is built for longevity.
In particular, you can do cost-efficient archives to multiple tapes and store them in safe locations. If (and that's a big if) the base cost of the drive is tolerable.
There was recently a wonderful post and discussion on LTO for "normal" nerds [1].
[1] https://news.ycombinator.com/item?id=30099540