I think the tendency for people - especially men - to be sexually attracted to youth and beauty has a natural basis that works toward perpetuation of the species. Not the tendency to be attracted to bean-pole women or to consider a 35-year-old woman "old," but the tendency to be attracted to those who seem to be capable of producing children and to be attracted to healthy-looking individuals.   That means it's probably not culture that makes men find "senior citizen" women less sexy than younger ones.

This, however, does not explain the desire/need for "news anchors" and political commentators or political leaders to be in their twenties or at least look like it. And I don't think we would expect that if so many media celebrities didn't have so much plastic surgery, makeup, etc.   (Nobody disrespected Walter Cronkite or Franklin Roosevelt for not being young or looking like movie stars.)

As for the beauty product ads -- ever notice that the models they use in the anti-aging products commercials are almost always actually in their teens, twenties, or early thirties?
Even assuming I believed the ads were honest, I'd be far more persuaded if I saw how the product worked for someone over 50.   

And I'd be much more impressed with how well some celebrity was "aging," if I knew they had not "had work done" and the image I was seeing was not one of someone heavily made up being "shot" with a soft-focus lens. : D