it kinda made more sense to me than the current setup where you have certain races living for so much longer than others, but they all get the exact same bonuses, just at different times. yet another example of illogical effects in the rules. if a race lives so much longer than another, then it should get wiser from the extended experience, at least in theory. ^^ anyway.
Actually, I can understand it, from a certain point of view. It make sense for races with significantly different lifespans to reach the different stages of life at different times, especially given that the relevant age categories here are middle age, old age, and venerable. An elf isn't considered mature enough to go out adventuring until he's roughly 100 years old, by which time a human is already dust in his grave.
It wouldn't make any sense to give bonuses intended to reflect maturity and wisdom to an individual who is only now barely considered to be an adult.