that laser beam burned a hole in Nixon's skull
the auden's quote's key word may be 'materially'. reminds me of a Dylan quote, (me paraphrasing) but along the lines of, "If i had been a doctor and saved one life it would have been more important than all the songs i ever wrote."
it's whether you're talking about material/tangible changes, or spiritual/aesthetic changes.
cuz there's also Nixon's quote, "If we've lost cronkite, we've lost the country."
and i don't know about the vonnegut quote (you're sure this one's not a hoax, right? :-), but i can tell you, after studying the vietnam war and the american citizen's reaction to it, and talking to a lot of people who lived thru it, they all say there was this gradual opposition that steadily grew until it reached a sort of critical mass.
i'm not sure what he's meaning in his quote because the artists certainly did help bring an end to that war, most famously Laugh-In on TV, M*A*S*H on the big screen, George Carlin and Richard Pryer in the comedy clubs, and everyone from Country Joe and the Airplane to CSNY and Peter, Paul & Mary were voicing it on the radio.
so i dunno if Kurt had some bug up his butt that day, but there is no question that it was a popular turning of sentiment against the war that forced Nixon to start the withdrawal (when he was actually starting to and wanting to Expand the war into Cambodia).
so, don't be depressed. it Was the artists speaking out that opened the way for the bulk of the country to follow.
oh yeah, and there was this one tall skinny vet who led other vets out to the Mall and Lafayette Park outside the White House who added a lot of credence to that revival of peaceful resistance. and this year, that anti-war vietnam veteran protestor is going to get to be President. so there is something to this protest thing.