Access to more and/or better resources is a definite competitive advantage in that they can give you an edge in one or more of the other success factors.
Should your setter take every ball, or should they be able to call for help on balls far away? I actually think it's a question with a mistaken focus.
In August and September of 2019 I spent nearly 2 months traveling around Europe observing a variety of volleyball teams and organizations.
Admin work doesn't get a lot of attention in coaching. If you get it wrong, though, it can have a big impact on your success.
The management of the competition phase probably isn't the biggest driver coaching success, but it definitely matters - especially when margins are narrow.
Your relationship with your players - both individually and collectively - can be a massive influence on your success as a coach.
If your training sessions produce better results than the competitions' - even if only by just a little each time - your chances of success go up.
A coach who is skillful in team organization is one who gets the absolute most of their personnel. This is a major driver of success in a team sport.