Strength and Conditioning Coaches in boxing. R they necessary?

Do you think the training regimen S&C coaches implement with their world-class fighters make a huge impact in the ring? Do they really make a difference, if fighter A stuck w/ old school S&C work, like good ole roadwork and trying to catch a chicken for agility and some pull-ups and push-ups. But, fighter B has a S&C coach and has all the new ways to condition a fighter. Fighter A & B's boxing experience, natural talent and skills are all comparable. Who wins?