It's brinkmanship though isn't it. It's easy not to blink first when you ain't bluffing. Let the EU play their daft game, we can "hard" Brexit at the appointed time if they fail to start acting as reasonable adults.
We don't need to be gone today, starting from scratch. What we must ensure though is that there are no extensions to fritter away time after time ad infinitum. We have a deadline, everyone knows it and should focus on it. If the EU is still refusing to progress and still having the audacity to be blaming the UK, (fooling no one) then they will have run out of time. WTO it'll be.