In very broad and entirely unbinding terms, some women have always found older men attractive because younger men are chaotic, emotionally charged, erratic, and not as safe a bet as an older one. This is normal human behaviour, or at least a variation of it, not some one-up men pulled on women.

I say unbinding in the sense that its a general pattern and far from a hard rule.

Looking to be in the prime of your life will always be attractive to the majority of people.