[AndroTux]

For the third time: IF you take care of the data, it’s fine in both cases. If you neglect your beloved book for 70 years and store it under a bridge, it’s going to be completely useless as well. The key part is the taking care of your medium.

[RandomLensman]

The taking care of the book for 70y does not involve recreating the book over and over again to keep it readable or keeping a reading machine in working condition (or be able to recreate it). It's an entirely different level of care.

If the medium isn't destroyed, it is directly readable if it's a book, but not necessarily so in digital because hardware and software is needed - just taking care of the original medium isn't enough in digital over centuries.