Top hits are just designed to be as agreeable to society as possible. That’s what makes them more popular than anything else.
It’s like claiming salt is causing a food monoculture because so many people are using it.
A culture is what people (more or less) share. That part is very narrow today, when it wasn't e.g. in the 60s and 70s.
Niche genres people listen in addition to the top hits but don't share don't enter the cultural sphere.
>It’s like claiming salt is causing a food monoculture because so many people are using it.
No, it's like claiming that whereas once people used to see a variety of movie types in the theaters, now every second movie is a superhero one.
That's true for what people see in the main, and it's true as to what the celebrated, talked about, and influential movies are, even it's easier that ever for everyone to also download and watch some niche movie from whatever era (which most don't bother).