Adorno saw opera’s decline as shifting class patronage toward concerts

Evidence

Opera, he argued, had lost its appeal with the upper middle classes, although the petite bourgeoisie was still attracted to its repressive elements. Instead, the upper middle classes increasingly patronized concerts, which provided a false sense of subjective inwardness and suggested a phony reconciliation of property and education. The search for true inwardness, however, was no longer realizable in modern society. Richard Strauss was the last meaningful “bourgeois” composer, but even in his music, as Ernst Bloch once pointed out, all negation had been lost. As he used them, chromaticism and dissonance had lost their critical power and become emblems of world economic mobility. — Martin Jay, The Dialectical Imagination, 562