Hmmmm ...it seems to me that just because you were born after the story took place, or even long before it took place shouldn't be the determining factor on whether you like a movie or not. In the case of this one...probably the baby boomers can relate to it better and, frankly, I didn't think the story was all that great. The acting was good, but not enough to make it a fine film. There are those who just love it...(like my own daughter), but she is a baby boomer so your point is well taken there.
And many really praise
American Grafitti who were not of that generation. It was just good and appeals to everyone even though it is about the sixty's generation and launched such greats as Richard Dreyfus and Harrison Ford.
Also it is interesting in that Kevin Costner had a small part in
The Big Chill..He played the corpse in the beginning of the film, but you never get to see him--because they cut out the flashbacks in which he appeared. Just as well cause he was destined for better flicks.