I dunno, it seems like you could say Dumbledore's Father and Mother defeated Voldemort, they had a child who was intelligent enough to do those things you said.
More seriously, it was a causal chain. Pretty much everyone involved was crucial.
If I had to give credit to one party in particular it would be the entity or entities which hands out prophecies (I suspect this is Future!Hermione, but we'll see). Voldemort's first defeat was caused by his attempts to fulfill the first in his own way. His second was caused by his attempt to comprehensively thwart the second.
Did he actually thwart it or will it happen?
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 114, and also, as a special case due to the exceptionally close posting times, chapter 115.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)