I think about this exactly from time to time. Pulp Fiction was maybe the biggest WTF moment I've ever had in a theater. I couldn't believe the ride I was on...the one movie I've ever gone to in the theater, and then went back the next night to see it again. I was totally blown away by it.
In my mind, it hasn't aged all that well for a few reasons...
1) You can't take it out of it's release time. It was absolutely a groundbreaking, industry-shaking movie that totally changed the game. It legitimized "independent film" and what it could be. In my opinion, when Pulp Fiction hit, we were coming out of basically 10+ years of generally piss-poor cinema. Then you get 1994...Pulp Fiction, and several other great movies, changed the game. However, Pulp Fiction suffers greatly on viewing now, based on all the movies (and TV) that came after that pinched the tone and the style. It's absolutely impossible for someone to watch it now for the first time and appreciate how "fresh" and different it was, and unlike anything that came before. The most magical part about it is impossible to recapture.
2) Once you get dulled to that dizzying high of the dialogue, the music, the broken timeline, etc...and start picking apart some of the narrative...it's not that great of a narrative, particularly some of the boxer timeline and the Marcellus rape situation. Without all the bells and whistles...some of that is not so great.
3) It's incredibly cruel. This one's probably on me, watching it at 42 vs watching it at 22. I just don't find all the laughs I used to. I don't find rape hilarious, or people getting killed accidentally, drug overdoses etc the way I once did. I am not "feely" about that kind of stuff, and I don't think it needs to be taken gravely, but the jokiness around that stuff just doesn't work like it used to, in absence of actual jokes.. The movie has an incredible lack of any semblance of heart at the center of it, or anything at all below the shiny surface, making it a bit more of a fireworks show than a great film.
Which is to say, I think it's a great movie and has a very important place in cinema history, and deserves a very high status. Everyone should see it. It's one of, if not the most important movie of my lifetime.
And at the same time, I'm not all that interested in seeing it any more, and when you show it to younger people (two of my kids so far, one to go) I think them being less than impressed with it (as my two have been) is a perfectly reasonable response.
Side note...I think Jackie Brown is a masterpiece. I went to see Jackie Brown in the theater and wanted to ask for my money back I was so disappointed. Couldn't have felt more let down by it as a follow up to Pulp Fiction. Watched it about 5 years later, and couldn't believe how good it was. It's a complete movie...great story, great dialogue, complete multi-dimensional characters, strong emotional connection...so good. It's really sad that it got such a poor reception, forcing Tarantino to over-correct and just double down with more spectacle and abandon full movie-making.
I feel like it's a little as if people had reacted to Close Encounters of the Third Kind with a resounding "BOOOO! F-- you Spielberg, more sharks less people!"...and he basically complied, making a series of monster movies rather than what he did make over his career. I would like to see Tarantino make a proper movie again, because I do think he's a genius.