Ex pro triathlete here. A better way to state this would be, "the training method matters much more than the athlete". These 3 guys are all very talented, but what sets them apart from other pro triathletes is the combination of their training style, group environment, and mental approach to the sport. These guys have mastered the art of:
1. Absorbing very high volume training (30-35 hours per week), over the majority of the year. They do this by performing their easy workouts at a very low intensity.
2. Controlled intensity. They use lactate training for most of their hard sessions. They never go over the top with their workouts.
3. Monk like training environment. No distractions. These guys eat, sleep and train. They do little else. They do this to a more extreme level than any of the other pro triathletes that I am aware of.