Since magnetic tape storage emerged in the early 1950s, its death knell has been proclaimed so many times, it's become an industry joke. Tape is still less than half the cost of disk drive storage.
On the left is an IBM 726 tape drive (circa 1952), which held two 1,200-foot long, half-inch wide magnetic tapes. Each large reel could hold 2MB of data.
Today, tape cartridges (think 8-track tapes), can hold more than 6TB of data. By 2022, cartridges are expected to hold 128TB.
On the right is an IBM TS3500 tape library. A base tape library cabinet can store up to 12 TS1140 tape drives and 260 4TB cartridges, or just over 1PB of capacity -- enough for more than 13 years of HD video.