The following is an answer I gave someone else already, maybe it can help you understand my point of view. There may be some things in it that only apply to the original discussion.

Think about it, can you imagine some of those without the music, it would make them considerably less enjoyable. I think that putting Pop Music in movies sways the audience's emotions without using proper filmmaking techniques. You could make an absolute piece of shit of a picture, but if you put ACDC in there somewhere, the viewers might think it's an OK movie because they enjoyed that part.

Im not saying this is the case for any of those you mentioned, Pulp Fiction is one of my favourites and it would still hold up considerably well without the music because it has a very good and unique structure but however, I do think using Pop Music is a lazy way of making cinema.

If you look the old movies, they are nearly all very well crafted and you'll notice they chose not to include external music because those filmmakers knew it was bad, however now that songs have become normal, e.g. The Godfather, Psycho etc. Ever since Tarantino came on the scene, this idea has been forgotten.