I want to resist, but it is Sooooooooo tempting to go along with the notion that the only reason sauron did not stop the hobbits was because Gandalf's plan was too stupid to be believed.
I have to remind myself that gandalf believed in, indeed fucking embodied, the intervention of gods that had established a millenia spanning precedent of doing fucking nothing, or next to nothing, for middle earth.
Nobody was expecting ANY help from the divine side of the equation coming sooner than the apocalypse.
It's an important, recurring theme in tolkien's works that illuvatar and the valar will leave middle earth in a heartbreakingly sorry state for millenia without getting involved. It's this attitude of "It's too fucked. it's not worth trying"