We misinterpreted a major vision of how 'Game of Thrones' will end

As we've learned throughout Game of Thrones, visions and prophecies in this world are a double-edged sword. 
At best, they provide real foreshadowing, but hardly ever for the outcome we initially expected. At worst, knowing these visions only makes characters fulfill their own ill-fated destinies in attempts to avoid it.
All of that seems to be the case for the most vital vision on the show, from all the way back in Season 2. As one Redditor is proposing, we might've misinterpreted a key pa