I'd say probably Bernard Hermann or John Williams. I'm fairly certain their music will still be relevant 100 years from now.
It's difficult to say about our contemporaries like Hans Zimmer etc. We are in a cultural bubble after all and it's difficult to say what will transcend.
It feels like anything post 2000, maybe 2010, is temporary, and absent of longevity and legacy. Like a tasty meal that will be forgotten tomorrow. Whereas the classic film/TV/Music prior to 2010 feel more like fond memories of a great family restaurant that produced many excellent meals and memories before closing down.
I'm fully convinced that if the most influential and coveted musicians and artists were starting out today, their music and art wouldn't make it out of their bedroom.
It felt as if music and art was a real part of life growing up (and I'm not even that old), but particularly in the last decade, it's become background fodder for the average person. I see it with my own family. My father has an excellent 5.1 system, yet, listens over a tiny Bluetooth speaker 99% of the time. My mother will have her playlist playing through her iPhone speaker while she does her makeup. I just hate seeing all those juicy bass frequencies abandoned for the sake of convenience.
On the flip side, you have people who are OBSESSED with audio and have adopted things like Atmos and completely immerse themselves in the full sonic spectrum. Far from convenient though. Wouldn't it be great if Atmos equipped listening rooms began popping up everywhere? Like a cinema for music. Go in and spend an hour listening to your favourite music/a new album in the dark or with some sort of visual show.
Most everything feels like a cheap trill these days. It's getting even worse when you have things like TikTok and YouTube Shorts that reward tiny tiny clips of music/film. No time to tell a story. No substance. People don't even know the name of the artist they listen to anymore. They just put a playlist on in the background. They probably know it as "Oh, that's the song from that 'Chillout Vol 1' Spotify playlist" (This is speculation though
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That's why I try to make time for people who want to share their music with us here and other forums. We know what goes into it. The learning curve, the 'soul', the time spent.