Fitness coaches are interchangeable. They either have the skills to develop a program or they don't, and these days I'm sure there's apps that will generate your program for you. What determines a team's fitness is its senior players. Conditioning work is painful over long periods of time, and some blokes just have what it takes to push themselves that extra mile. The ones who don't have what it takes can still be motivated by others, but it's not coaches who do this; it's teammates going through the same torture in the moment. Blokes reach quitting point and think that's it. The fitness coach doesn't know how much he's got left in the tank, but his mentally stronger teammates can show him how much more he's got. It's not the quality of the coaching; it's the quality of leadership that matters for team conditioning.
Source: I experienced this in the army. I've done so much conditioning work that I'm not even 50 but riddled with arthritis.