Women have aprox 10 years of peak fertility.. peak time of attractiveness. Raising kids (the ultimate goal of sex and sexual attraction) takes 8 years after which the kids start to get some independence and rely less on their parents, but more on the "community" - peers, friends, other relatives, etc.
There's a new first kid in town.
www.hollywoodreporter.com
Successful old men having kids w/ younger women have been happening since the beginning of time. Just by living so old, these men have a proven record of having superior DNA at least, for the most part. Because of the "soft" environment we are living in now, some old people are just idiots. But in general through out history, living to old age means these men are resistant to cancer, and other alignments. I think that is why a lot of women are attracted to older men. It's a primal dna thing.