i’m not an expert on hard drive but here is what I think, It is possible that hard drive will disapear but I thik that the Flash hard drive will be use more for getting faster cash I/O than replacing hard drive. Look a the new SUN NAS. they are using 10k RPM SATA drive disk with flash drive and the seem to have the fastes NAS of the industries. But technologie wise I would say get ride of all mechanics and yse only electronics part. so you illiminate a point of faliur. The day we will see flash drive of TB is probably not far ahaed but to replace hard drive that is somthing hels.
Last week I had a chat with one of the main storage vandor and they are gooing fast forward on flash drive. It seam that hard disk drive will extinct and sooner that I tought.
here is an article that ask good questions when a company think on changing to flash SSD drive