The players needed to run the same offense weren't on the team before.
Hay, Tiller on the OL, Bailey all by himself. Who's the third receiver last year?
That's fine and this is a pointless argument b/c either way DM and Hackett deserve credit for putting together a more or less unstoppable offense. BUT, if you buy into the narrative (I'm not sure I do) that they decided to go up-tempo 3 weeks before the season, then it wasn't a matter of waiting for just the right personnel mix. It seems to me it was a shift in offensive philosophy and the proper personnel.