there's some fine lines between hamfisted theme-ing via musical choices, intentional irony, and just some shit a film freak likes listening to

for example: Hudson Hawk is a movie about criminals, but the inclusion of 'Swinging on a Star' amongst other 'oldie' standbys isn't connected to a statement about that music, though it is next to crime shit and beatdown shit. it's because Bruce Willis is a boomer and liked that song, and created a diagetic excuse to include it. which brings up the next thing, filmmakers are 10+ years older than the subjects they 'speak to' as artists. their musical choices and tastes are necessarily older than the era they come to represent. Tarantino is the 90s movie guy, his musical sensibilities lie in the 70s and 80s.