Because the expanse is a book that was adapted into a show

It's nowhere near "good music doesn't exist anymore". They are the same old plotlines with that double crescendo bullshit. The only thing that really changes are the characters and setting. Sometimes they add a twist here and there in order not to be too obvious, but if you watch enough stuff, they feel the same.
Trailers have genres themselves. You can watch a trailer and know nearly the entire plot of a movie plus what the genre is. The colors also give away so much about that: blue - technology, dark tones - horror, greenish blue - techy sci-fi, colorful - probably art-house, etc. there are entire pallets dedicated to genres and their subgenres.
The way the cameras move, the chosen audio effects, scenes that unnecessarily capture a specific object or center an unknown thing, a few frames of a look, and so much more.

Writers and the creative personnel have been hamstrung by the focus on ROI. Remakes and sequels are the biggest investment these days. There's very often some attempt to build a franchise or continue one.

Music has changed massively. Outside of mass media, you can't take a song from now and say "wow, this sounds like something from the 80s". The red hot chili peppers, black sabbath, metallica, and other bands used to be considered metal, but that's unrecognizable as metal nowadays. Maybe rock?
Music has mashed together so many genres that you can go and type nearly any genre in a search engine to find music of it.