I cannot find the reference, but some days ago I read an interesting article where they compared the recovery of younger and master runners. They did ask the runners of their percieved recovery state and they measured markers for recovery or fatique in the muscles. The interesting finding was that the master runners reported they felt less recovered, but they actually were as recovered as the younger runners.
I do not doubt that there finally are effects with aging that makes it harder to do what we did when young. Power, flexibility, HR, VO2max, and so on decreases, but We can also see that the even elder sedentary people can improve at the same rate as young.
Maybe all the wining about longer recovery at least partially is in our minds and a placebo effect (really a nocebo effect since we anticipate a stronger negative effect from training in the form of longer recovery).
Maybe building muscular resilience by becoming strong and fast through heavy strength training and hill sprinting, together with keeping the dynamic flexibility is important in feeling one can do speedwork and recover from it. I do feel I get more aches and becoming stiff, but still I could very well do a long fast threshold when I just get going. I think recovery is different aspects.