The DAO did exactly, exactly, what it was supposed to do. In no way can it be have said to fail, except in the "wasn't a great investment" sense. Maybe in failed in the "wow using terrible languages to write complicated code is a bad idea" way, too.
Ethereum failed, as they decided smart contracts aren't a great idea, so they're now going to involve humans when they feel like it. The whole premise of Ethereum was the opposite of what they're doing.