I think that being able to ride alone should be the goal for everyone that wants to ride endurance. This would be both in training and at competitions. It is very seldom that two horses are perfectly matched to travel at the same pace. It is quite a responsibility to put on a fellow rider that they must ride with you because you are not comfortable being alone on a trail. I think that bonding between horse and rider can only happen when you are alone on the trail and the human is not distracted by other riders and the horse not reacting to herd instincts.
Everyone has a choice on how they decide to ride endurance. I felt a little sad when I read that one would pull from a ride if their riding buddy (human not horse) was not continuing down the trail. There are so many different reasons not being able to continue down the trail but I never considered that one would be because a friend or riding partner could not continue with me.
I guess I should consider myself very lucky that I have no fear about riding alone. I know there is more risk to be on wilderness trails by myself, most of the time with no cell phone service even if I remember my phone. But I have decided that the risk is worth the experience I have when I do ride by myself. Personally, I would not want to have to rely on another rider to be able to participate in this sport. There may be a time or come a time when I do need human companionship to ride on the trails. I had never really thought much about it before and take the experience of being able to ride alone on wilderness trails for granted. The original post really made me think and realize how lucky I am to be able to go out alone with my horse and not be fearful or worry about all the things that can or could go wrong.
I prefer to take my green horses out by myself also. When riding the youngsters or the youngsters, I have no problem spending a lot of time on the ground if I am not comfortable on their backs. Riding alone gives me the opportunity to work on training issues and alter ride plans to fit a particular horse's needs that day. I have spent an incredible amount of time working out a trail issue or obstacle and may not get further than a 1/2 mile from home. I would never be comfortable doing that if I was riding with another person even if they didn't mind.