Ramon Chen, of Rainstor, in a long, Q&A-styled article about Addressing Big-Data Challenges. Unfortunately I know this behaviour he mentions just too well:
At a more granular level, organizations continue to retain critical, structured, transactional data in production system environments far longer than is legally required. These primary systems quickly become bloated and require ongoing capacity planning to accommodate anticipated growth.
Tape is often used not only as an operational backup, but also as a long-term archive. If you’ve got thousands of tapes, that quickly becomes unmanageable…