Back in December I found myself at dinner with a (and I mean this lovingly) gray haired technology vet - someone who could spin tales of young Jobs, Ellison, and other Valley luminaries. Over the course of our conversation the idea of obsolescence came up - not of gadgets, but of people. Do most creative folks have a half-life on their ability to invent innovative uses of technology?
I think the answer is definitely "yes," especially if you're focused on the consumer space. I'm fairly certain that today's toddlers are growing up with an understanding of technology which is very different than what I was raised with. A few generations after me and people start to look at ordinary objects is very different ways - newspapers, telephone landlines, the VCR are all anachronisms.
As I started to calculate my own expiration date (still pretty far out!), my companion noted succinctly that the way he always thought of it as "ideas vs experience." That successful folks traffic in both but somewhere along the way you peddle more of the latter (which helps you recognize and execute on good ideas).