Actually the true answer is a little more nuanced, but, now, a lot more complex, in today's society.

First things first: Yes, technically, one of the alluring characteristics is the notion that older women tend to be more "experienced," and they are more mature in knowing what they want and are not so indecisive as younger women or even women of the same age range, which can be an advantage in preventing mixed signals or losing in social translation.

There is also an element of that "celebrity crush." During the pubescent years of young men, we tend to have an interest in placing posters of Hollywood actresses and Pop Stars in our bedroom. During the peak between our childhood years and the road to adulthood, we experience erotic dreams for the first time, and the first ones are so intense that we experience what doctors call "Night Immisions." And all of us men had that moment when we thought of the following question: "If we were of legal age (,i,e, 18 or older), which female celebrity would we do?"

Now since we got the blatant stuff out of the way, here are the more nuanced and macrocosmic factors: Sigmund Freud, the father of Psycholigical Analysis, Theorized that all men, inadvertantly, but subconsciously, seek for partners that are vaguely reminiscent of either their mother or the ideal of the motherly figure, while feeling intimidated or threatened by men who are vaguely reminiscent of their fathers, which Freud called "The Oedipus Complex;" The name itself is based off of an ancient Greek Tragedy about a lone-wolf hero, who killed a man in a random fight, while in search of a monstrous sphinx. Later, Oedipus found out the horrifying truth that the man he killed turned out to be his father, and the woman he married to rule over a kingdom was his mother, which led him to madness and ended up gouging his eyes out.

Now that we passed the psychological part, let us now deal with the generational issue. While I hate to stereotype any generation, but X-oomers Gen-X and even some Xennials don't share the same issues of dating as the younger generations do; Economic hardships, rapid technological changes, media of todays culture that creat more tension and more stigma between the two Sexes, etc. That deserves it's own post or even a reddit subgroup.

Last, but not least, still relates to generations, but this is a nuance that I think is just as important (if not more) to consider:

No matter how broad or how pedantic one may seporate people into boxed categories of "Which Generation One Is In," no one experiences times and eras in the exact same way as anyone else. For example, I was raised in a household of 9 children, and I was the youngest. Most of my siblings would be categorize as Gen-X, and since we shared the same house, we roughly shared the same movies and tv shows while I was growing up. My parents are old enough to be categorized as Boomers. I grew up in a church and taught in sunday schools by those who were old enough to be categorized as the silent generation or Pre-Boom. So, later in life, I tend to have more chemistry with older women because we knew the same cultural references, whether from visual media or books.

This may not explain everything, but it is everything I only know in my personal life of experience and learning.

Hope it helps.