Tape is still used for archival purposes, as it has very long shelf life (i.e. longevity when not under heavy usage) and low cost per byte of storage (fancy electronics go into the R/W machine and the library hardware, not the tapes). AWS Glacier (https://aws.amazon.com/glacier/) was built to replace on-premise tape libraries, and while no one knows exactly what storage medium they use, a tape library is one of the possibilities given the pricing model (cheap storage, expensive retrieval) and retrieval delays (on the order of hours, unless you're willing to pay extra for on the order of minutes). Other possibilities I've heard thrown around include I/O-poor NAS boxes, and a tape-like mechanical library of optical disks.
I recall reading somewhere (pretty sure it was actually here) that Glacier used some sort of custom low-RPM spinning rust that could be spun down when not in use and otherwise took very little power.
No one really knows - there have been leaks saying multiple contradictory things over the years, which leads me to believe they're experimenting with a variety of storage technologies.
