The authors you pick up early, whom you read your entire life -- so they are like Dickens in their always having been there, but they are still coming out with books. Except of course that in due course you can't because mortality weeds them out. One panelist had seen all but a couple of the writers she had read as a child die.
One discussed the impact of such writers as influences, and how Ursula K. LeGuin's "Nine Lives" was told over and over again, unlike Heinlein's Starship Troopers which inspired works but not faithful homages.
The way readers, as they age, stop finding new favorite authors because they can't keep up with the new stuff, or perhaps can't acquire a new taste.