The moral of the tale is ten cents worth of oil applied every week (the manufacturers recommend oiling daily!) reduces many of these problems. Shark fins indicate a worn chain eating a perfectly good chain-ring - a ten dollar chain eating a fifty dollar and up chain-ring. Some of the chain oil bath bicycles I've worked on have chains and crank-sets that are a hundred years old. They look brand new. The epicyclic ones have 150 ball-bearing in the 'BB' to lubricate as well - they also look new. Certainly they are made of much stronger materials ( the chains are impossible to break with a modern chain breaking tool) and the split link is literally bolted together but without constant lubricating oil they would not last much longer than modern components - leave alone a hundred years.