It makes perfect sense to retain things like sales orders, financial transactions, court records, and health records in digital format indefinitely, because there may be an essential need for this historical information at a later point. But this type of normalized transactional data doesn't consume nearly as much storage as stuff like surveillance video, IoT telemetry, click stream, and binary objects.

The fact Susan deposited $100 to Tom's bank account back in 2004 may still be relevant today or even 10 years from now. The fact that Susan liked Tom's comment on FaceBook yesterday has questionable value today and will be totally irrelevant 10 years from now.