The origin of the distances for the Ironman triathlon were discussed in a previous question, but it seems odd that almost every triathlon I see, the swim section is incredibly short in comparison to the running and biking section. Why aren't triathlons set up to be 1:1:1 in either distance (e.g. 1 mile each), or in time (e.g. how far a 95th percentile athlete in each sport can go in an hour)?
If anything, I would think that the swimming section should be proportionally more, since it's the only part that substantially works the upper body.