I think why we disregard old material is because we were bitten by that while we were learning programming in the first place. The web is full of old cruft that no longer applies, and some of it flat out dangerous, so we shun older information in favor of newer information.
Haha, you are proving my point "the web" indeed, this problem has been going on for long before there was "the web", tho' the web has certainly made it worse, everyone thinks they're using the latest greatest thing, they don't even realize that it's just yesterday's leftovers with different buzzwords attached. That's the tragedy here. And who is to say the new information is any better? At it's very best, it's just repeating what has gone before. Why not go to the original, and learn for yourself?