Michael Chabon's keynote speech at this year's Eisner Awards captures, I think, one of the key elements that drew many, if not most, of us to comics. Really not "one" element but intertwined sense of wonder, richness of world, clear but not quite clean morality, and above all an encompassing sense of storytelling that has room for life's quieter moments just as much as super-intelligent, talking gorillas.
His reasons for a decline in childrens comics are reasonable and likely true but he avoids the all-too-obvious economic factors. As comics, at least American ones, retreated from newstands to comic stores there was less and less incentive for creating childrens comics and in fact as Chabon points out a feeling that comics should be distanced from that. But how were kids to be drawn to comics stores--that are often designed, consciously or not, to repel outsiders--even if the goods were there? The recent explosion of manga in the U.S. shows that there was an untapped market though it's still way too early to see how much of this is a trend and how much will actually stick (& more likely the former if Tokyopop keeps flooding stores with barely distinguishable books).