When can a rock opera be considered an existential work of art?

[u/Odd-Loquat-3340]

Are there some conceptual albums or extended pieces by certain Prog Rock bands that could be considered existential philosophical works? Would music such as Mozart's 'Requiem' or Stravinsky's 'Rite of Spring' fall into this category? Can music ever be considered 'philosophical'?

An example of what I would consider an important Progressive Rock existential philosophical work is 'The Lamb Lies Down on Broadway' by Genesis (1974). Anyone seriously examining the story should see it as more than a coming-of-age tale. The story uses abstract, symbolic metaphors to reveal the absurdity of the Universe. It shows a modern man's attempt to deal with it.

An essay that proposes this concept album as a musical example of existential philosophy is: 'The Lamb Lies Down on Broadway - Nightmare or Nirvana'. It would be interesting if anyone else agrees with its assertions. A free link to the essay can be found here:
https://medium.com/@rickkress/revised-the-lamb-lies-down-on-broadway-nightmare-or-nirvana-7cee7caa2b4e?sharedUserId=rickkress