We can run the route once—why does repeating it wear us down?

You ran the route. It worked. That felt like proof. But one clean run proves less than you think — it proves you can do a hard thing once, with fresh legs and full attention. The real test is the fifth time, the tenth time, in worse conditions, when no one is watching and the novelty is gone. Wearing down is not a moral failure in your team. It is what happens to any group carrying repeated load with no system for sharing it, no honest way to say 'I'm slipping,' and no plan for what changes when conditions turn. Blaming effort here is comfortable and useless. Look at the structure instead. You cannot control how much volume comes, or how hard the conditions get. You can control how the load is divided, how early someone is allowed to say they're struggling, and what you cut when more gets added. Build that, and the wearing-down slows. If it turns into something heavier that rest doesn't touch, that is beyond what any method here can fix — get support built for that, outside this room.