Listened to Born In The USA album by Bruce Springsteen the other day and it struck me that the line "our Pa's each own one of the World Trade Centers" in Darlington County wouldn't be there if the song was written today (ok, it could, but very unlikely).
Similarly, Paul Simon's Kodachrome wouldn't flow out of any current writer's pen - again, there'd be nothing to stop it being written but it almost certainly wouldn't be.
Last one for now, I've just heard the Beastie Boys' classic Fight For Your Right and the line 'your Ma threw away your best porno mag' probably wouldn't mean much to today's frustrated teens and their unlimited online supply of grot...
Any other suggestions for lyrics or song themes that have been rendered obsolete or at least very outdated by events, the march of technology etc? Was thinking of factual reasons rather than just general change of fashions, song styles etc.