Terex, I do hope ebooks created today are still available 150 years from now. For sure the reason Scott's journals are available now is because they survived the 100 years in paper form. If it had been electronic who knows? I do know I do not have a computer today that can decipher a floppy disk. If all my writing had been saved to a floppy, what would I do? Find someone to move it to another format? Could that be done 100 years from now? Doubtful.
Some may comment, "Who cares?" Many folks do. This subject has been brought up plenty of times with "geeks" I know and we all have similar concerns. For example, how do I run data created on a punch card system? I can't. Don't know anyone who has such a device to decode them, but I remember them from my childhood. All that data on those cards is lost, non-recoverable.