I don't think there's necessarily a difference, moreso that we entered the discussion with a specific movie that resonated with the exact life period and identity issues that a certain generation was experiencing at the time it came out. I'd call that a subset of the category "culturally relevant".
Likewise, I think something like Titanic was as culturally relevant as Pulp Fiction in the wider definition of the term, even though the people who deeply loved the movie Titanic and saw it OVER AND OVER in the theaters weren't exactly survivors of a shipwreck... Just like I saw The Matrix twice (or maybe 3x?) in theaters, something I'm not sure I can say about any other movie. Yet I don't identify with someone living in a simulation as batteries for AI... Give AI a few years before we get there, wouldja?!