Welcome to a mature market
5 years ago we changed drives because they were full.
Today we change drives because they break.
So any purchases are replacement only and (to make matter worse), replacement after the actual need has been well established so not bought with a lot of capacity to spare. On top of that a lot of the biggest capacity eaters - personal photos, videos, etc go straight to F***Book and do not linger around in 4-5 copies on the user's drives.