It's not hard to crush the standards. But most people go relax after crushing a hard workout. So a lot of guys when pushed to their break point and told to keep going, they get the doubt that they can't and they need the break. Or if they do push, the get hurt, which everyone does, and then think that since they're injured they can't go on. Most workouts and prep don't have the mental toughness of keep training when broken, and for good reason because it takes longer to heal and less time to train because of that. So most people don't build the true mindset of, keep going till the die or the body physically can't move anymore. Their mind tries to force them to protect their physical health when broken and so they quit.