Thinking about this a bit more, I can up with a good analogy-LEDs.
LEDs have existed commercially for ~35 years but were relegated to niche uses like displays and indicators until the advent of white LEDs about 10 years ago. Between ten and five years ago LEDs made inroads into some small illumination needs like penlights and keychain lights, or for specialized uses. In the last five years, LEDs have gradually displaced incandescents in almost all small lighting needs, and many medium ones like flashlights. Soon, they'll move to things like auto headlights and general home illumination, all but obsoleting incandescents within another five years I'd say.
Right now I'd say SSDs are where LEDs where a couple of years ago. They've made significant inroads into forms of storage which formerly used mechanical disks, all but replacing floppies and being on the verge of replacing things like zip drives. However, they have yet to touch even small bulk storage needs like boot disks. Think of the Samsung's new SSD as the first commercial LED flashlight with output rivaling an incandescent. This happened roughly three or so years ago, depending upon who you talk to. Information technology evolves somewhat faster than LED technology, so in five years SSDs may all but obsolete mechanical storage, taking maybe ten years total from the time it was first used in PCs until it became universal.
