I suspect the misappropriation of "Poetry makes nothing happen" (the mis- part well argued to be so here) is in part because the stakes are perceived to be so low. We can't define with any specificity what "something happening" would mean. This, taken seriously, might sober us up a bit:
As I've often told Ginsberg, you can't blame the President for the state of the country, it's always the poets' fault. You can't expect politicians to come up with a vision, they don't have it in them. Poets have to come up with the vision and they have to turn it on so it sparks and catches hold.