There is a reason the present begrudges the past," writes Harlan Ellison; I won't pretend to be wise enough to know what that reason is, but I believe that statement to be true, regardless. The evidence is plain in just about anyone beyond a certain age, the all-consuming, epic oldness where a person can say "when I was your age" without a trace of irony. It hits some people as early as twenty or so, when they suddenly find themselves on the downhill side of life, confronted with a bleak realization that things were a whole lot greener back when they were still climbing (or before they knew any better, at least). Some people, they just never stop climbing; it's rare, but it happens.
A great many of David Bowie's fans, with each successive year, slowly but surely creep into the former category even as Bowie himself manages to still act like a card-carrying member of the latter.