Maybe Jon Gruden ends up being Saints HC?

No we don't know that. There is no way to now that for sure. Belichick was 29-38 his last 4 years in New England. We are not one elite QB away from being great, this team has so many roster holes and aging talent. No matter who comes in, it’s not going to be a simple 1 year process it’s going to take time.
Yes we do know that in Belichick. And yes it will take time.