there is no practical technology for long term data preservation. you cannot save a computer file in a way that will last more then a decade. all counterexamples are meaningless; they only exist in a lab. anything you can actually buy will last a few years and then just disintegrate
it is continually astonishing to me that we just keep going through our days, doing nothing about this, while it grows more and more unlikely that any proof that we existed at all will survive us
