I like this idea, especially using git to version the store. With automatic commits, you could roll back to a particular date to see the page versions then. A personal "archive.org" sounds very awesome!
However what'd make it really amazing for me would be the ability to share those archived versions with everyone around the world, so we wouldn't have to duplicate our efforts or would have a higher chance of having that specific version of one special page saved.
For now the best way to contribute to this seems to be centralization: Donate to archive.org.