Re: Give it time
Consumer drives account for a small fraction of the shipped used capacity. My educated guess is most capacity is going in the data centre or at the very least consumer level NAS drives, for which SSD makes no economic sense. So unless there is a huge drop in the cost per GB of SSD's disk is not going anywhere. It's just like tape, need to back up 500TB, well doing that to D2D is just not economic even with dedupe.
So while spinning disks (there has been no spinning iron in disks for decades) may well disappear from end user equipment, and 10k/15k RPM hard drives are on the chopping block, the bulk storage 4TB+ 7200/5400 drives are going nowhere fast. I have a pair of 4TB 7200 RPM drives in a RAID1 and it happily could do six different simultaneous 720p streams from my Plex server. At that point I ran out of playback devices, in these sorts of applications SSD is not replacing HDD any time soon.