// Day 1 we should have laid out our terms and said we are prepared to leave with no deal if necessary ... //
The thing is, to an extent I agree with you on this point. But then that would have required an entirely different motivation behind the referendum even being called in the first place. Certainly, the lack of planning for the eventual result was atrociously poor (and, I think, deliberate on Cameron's part). But then that means that on day 1 it was impossible to set out our terms, because nobody knew or agreed on what they were, or on how to achieve them, or when, and so on.
If Leave had won, and had a plan for doing something with that victory, and if Cameron had called the referendum not to unite the Conservative Party but to actually have the question of our EU membership settled, then ... well, if only.