Wagner didn't revolutionize music, he killed it. It's hard not to regard Wagner as the absolute zenith of Western music. Before him, music was enslaved to form, after him, music loses its way in the trappings of atonality and we see the rise of disposable "popular music" in response. With Parsifal, music has seemingly served its purpose, and suffers a slow death, its fatal dying gasps can be heard in Cardi B's "WAP".
Old post, but I feel compelled to note that atonality was basically the antithesis of Wagner's aesthetic style that involved the tension created by the ambiguous, androgynous suggestion/co-existence of multiple possible keys and tonalities. The profound, impassioned yearning in much of Parsifal and in the opening theme/motif of Tristan is built from that tension. Atonality eliminated this tension by eliminating tonality altogether. You can't have tension without tonal hierarchies and the expectations those tonal relations create. Atonality, despite what some may say (including the atonal theorists) was not a logical progression from Wagner's ambiguous tonalities, it was a complete destruction of everything Wagner himself tried to achieve with his tonal innovations.
FWIW, I don't hate atonality myself and think many great works came from it; and tonality continued to flourish after Wagner as well with all the composers who chose not to buy into the dogma of the 2nd Viennese School and theorists. Plenty of composers continued to tread middle grounds between tonality and atonality, or alternative grounds altogether like Mahler, Scriabin, R. Strauss, and Messiaen. Plus, even if all atonality ever gave us Wozzeck I think the entire movement would've been worth it.
Also, as an aside, WAP is a novelty song. There have been dozens/hundreds of such songs that achieved temporary popularity and quickly faded from public consciousness. Musically it's just a typical Trap song; completely uninteresting if it wasn't for its scandalous sexual lyrics, which, IMO, are more funny than anything else.