Here's a clearer way to say what the TED speaker was saying:
'If you do that, then everything will fall into place, but if you don't, you will have failed.'
Yes, literally, she means 'will fail', but the correct English expression is 'you HAVE failed', as the speaker said. (you've = you have).
From a learning point of view, it is more correct to say 'you will have failed'. The logic behind this is that if a certain action is not carried out, then the person not only WILL fail, but once they've failed, they would say 'I have failed', so, looking into the future, they 'will have failed'.
There's no nuance: you can think of it as 'will fail', just keep in mind that you should say it as 'will have failed': it's just a strange thing about the English language.