>Once you're old you almost certainly won't be using modern software and file formats. Accessing your data will be incredibly inconvenient
This isn't true. Sure, no one uses WMV or ZOO these days, but you can still get tools to read them. But those were also not-so-popular formats/codecs that were replaced quickly by better stuff. MP3 is also old, but still very ubiquitous. Furthermore, the specs and software for modern file formats (like audio/video codecs) are all publicly available. People will still be able to read h.264 videos 50 years from now, don't worry.
This isn't true. Sure, no one uses WMV or ZOO these days, but you can still get tools to read them. But those were also not-so-popular formats/codecs that were replaced quickly by better stuff. MP3 is also old, but still very ubiquitous. Furthermore, the specs and software for modern file formats (like audio/video codecs) are all publicly available. People will still be able to read h.264 videos 50 years from now, don't worry.
It's not going to be like the Domesday Book.