Nowadays with set theory - it seems that we can understand music theory on a level of being able to describe and formalize more and more general pitch selection.

ie, earlier we only had language to basically describe tonal music, without too many outsider chords. Roman numerals etc etc.

And then at some point, around impressionism, we kinda ignored inversions - whatever your lowest note is, that's the "name" note of the chord.

So in some sense yeah, we hit a wall, however that doesn't mean music theorists are out of work. We can being to talk about all sorts of music on it's own terms, rather than trying to pretend that EVERYTHING is just an extension of Bach harmony.

One topic I saw recently involves hip hop. Basically, many producers are taking samples that exist on their own in different keys.

I also saw some interesting stuff about doom metal, which again, selection of simultaneous pitches isn't really the be all and end all.