Never known any rod to have anything to do with getting a fish to pick up my bait.
At the end of the day, if someone wants to pay ?750 for a rod, fine. As Roto said its up to the individual tastes.
Carbon fibre or Kevlar doesnt go "off" from what I can remember, well at least not with the usage a rod would get. I suspect any differences in "feeling" are down to better construction these days.
I have been a very keen skier since (well since I can remember) and if I may say, a bloody good one. One of my pairs of skis is nearly 20 years old and is no way "spent". And these things get really stressed out. So I would be surprised if they change that much.
There again, I am often surprised.