Since most of the modern musical genres come from Folk, Blues and Soul, is correct to say that in modern societies music came from the lowest sectors of the society and was taken by the upper classes and modified and mixed with other genres to create the ones we know today? I was thinking specifically in the music of the 20th century in US.
PS. I Tried to explain myself as good as i could but english is not my main language, so sorry.
Wow, this is an incredible question.
I can speak for jazz specifically, and say that it is in many ways connected to histories of oppression. Having evolved out of different genres of music that were pioneered by the descendants of slaves and second class citizens (the blues, for example, is often seen as incorporating aspects of slave songs). With that basis, it's hard to avoid story-arcs of oppression within the music.
I'm not sure I would sign off on a blanket statement of "all modern music being linked to oppression" however. I think modern country music, for example, has escaped this history and is now, in many cases, a music that reflects dominant society and not the oppressed classes.
Edit: For an interesting perspective, check out Nicholas Payton. He sometimes makes the case that the death of "jazz" reflects a change from an oppressed music to a bourgeoisie music.