My father told me he wanted to make USB flash drives of all the scanned and digitized family photos and other assorted letters and mementos. He planned to distribute them to all family members hoping that at least one set would survive. When I explained that they ought to be recipes to new media every N number of years or risk deteriorating or becoming unreadable (like a floppy disk when you have no floppy drive), he was genuinely shocked. He lost interest in the project that he’d thought was so bullet proof.
The problem isn’t even the hard drives, it’s how they are managing them. There’s not many digital data storage solutions around that you can dump into a closet for a few decades and then still read.
You have to regularly test your hard drives, so that when one fails you can take your other copy of the data and put it on a new drive.