I didn't bother hunting up a link to the study measuring objective trends in pop music because it was widely publicized in well-known sources like New Scientist.
Also, I knew full well that people so shameless as to claim it's all subjective and then still argue that there's progress would try something grossly ignorant, like trying to claim variety isn't a part of excellence.
Further, the objective facts of history show conclusively that whole generations have praised themselves, yet the test of time has decisively rejected them.
The inability (or refusal) to understand simple English may be useful to hide confused and incompetent thinking. But the fact is that mainly this is about indignation that old people don't appreciate the magnificence of the young. This is not an admirable thing.
And, skepticism is still opposed to materialism.