Mark Bernstein brings up the point that has always baffled me:
Wikipedia bursts triumphantly on the scene just as everyone had pretty much abandoned hope for the memory of Mortimer Adler's grand project to revive the encyclopedia.
Later... I guess this is a little different than I'd put it. Not so much that people had abandoned hope, but that the whole idea of an encyclopedia seemed antiquated. It is an enlightenment idea, certainly not a post-modern one.
This is, of course, closely related to Mark's later point that "it's been a full generation since people really believed that a neutral point of view was either possible or desirable."