Because some are repeated and eventually will be forgotten. The oldest one I know is little red riding hood and that one originated from Africa I think. It’s been a while since I did research on children’s/folk tales. Yeah, I studied that at university.
You misunderstand the purpose of my asking the question. It was not a request for your opinion, educated or otherwise.
To add a little more, they are used as a crutch to keep people in order. Until they become so powerful the meme becomes a religion. Until civilization is wiped out and it starts again with new players, same ideas.
This is the untenable position of the cultural cynic. Everything is viewed as a means of oppression and enslaving the human being - a foreign construct that need be destroyed to liberate the true godliness of the human spirit.
Bro, answer the question. It will answer the basic premise of the original post.
Once again, you misunderstand. I have already answered your question, and have, again, re-iterated the point at which you should explore through a question.
Further, your basic assumption is heinously flawed. Does every generation have their own love song? I certainly see songs being more cultural than generational. Each individual within a generation tends to identify more strongly with different songs from different genres and eras of that genre. Before the age of record and broadcast media, songs were almost a hereditary mark within the culture, and still are.
It is also interesting that there is a tighter association between genetic markers and the types of music a person likes than there is between the physical location of individuals, as well as a very strong basis for musical ability, itself, being heavily correlated to genetics. But that is a bit of an aside. The bottom line is that it's rather hard to substantiate the premise that each generation has their own love song, which makes any answer to that question you believe to be key to some profound insight... suspect.
On the other hand, we have absolutely ancient tales that have survived. The Bamboo Cutter, for example, predates writing. The epics of Gilgamesh have ultimately survived. Why is it that these tales survive? Why did tales of knights and dragons persist through bardic tongue? Why, centuries from now, will people likely still scream "Leeroy Jenkins" while charging gung-ho into a task or confrontation?
Why do some of these things just survive as they are, more or less, even while arguably better versions or re-envisioned works get made? Why will O' Brother, Where Art Thou likely fade into the realm of eclectic film history - while The Odyssey will be studied for generations to come?
Psycho-Pass is brilliant - a series I would absolutely love to make a faithful live-action of, as I know there are people who have difficulties wrapping their head around the notion of a serious cartoon. It is one of the most condensed and accurate depictions of sociological and governmental philosophy and the conflict thereof I have ever seen. It incorporates and references aspects of the works which it drew inspiration from - or pays homage to - and is perhaps the most powerful piece on the subject. It is a work that I believe should be mandatory for education, if anything in education should be mandatory. It is even more fundamental than math and possibly even writing, as it strikes at the very core of why society exists in the first place.
Will it ever eclipse 1984? Probably not. Even if it is remade as a live-action to the T of the original, with heavy advertising - it will probably never eclipse 1984. If anything, 1984 would raise equally in popularity with its mention in Psycho-Pass by Makishima. Which isn't a bad thing, at all. It is just that some things are more iconic. Almost every dystopian series is going to be compared to 1984 - just as Little Witch Academia will always be compared to Harry Potter, despite the fact that there is absolutely no comparison and LWA is better in every single way.
It is why Madoka Magica will almost always be compared to the likes of Sailor Moon - again, despite the two not even being the same genre (magical girl is not a genre, nor is mecha, but that is another story involving aldnoah.zero, battletech, Shadow Run, Sunrider and front mission with a dissertation on the evolution of the RPG, JRPG, and Mecha in general from Japan).