you are the leader of the herd, like the description or not. Or at least I hope you are because someone has to be and for the horse's own safety that has to be you. You are riding your horse along a busy road, something appears that terrifies the horse, your leadership will mean the difference between life and death.. Yours and the horses. You are not the "asker of silly questions" you are the boss who says "do it now" and the horse is the follower who understands he has to obey without question. As the leader you have given him the confidence.
I'm not sure people train to make interaction a battle of wills in fact I think most try to avoid that. I also can see no relevance to dogs and wolves. To me that just seems to be people wanting to come up with theories. Horses are very different animals.
You say there is no herd of two. How does your horse see that? You see your relationship as being the provider of resources how does he see it? Does he feel safer with you as his leader?
To get back to Irish Milo who is still missing an answer to her post. We are in the real world. The 16.3 three year old has had very little handling and most of it has been poor, he is in the stable and decides to exit over the top of the handler. Other than ask the silly question of "please don't do that" what are you going to do?
Another example you have just taken on a 2yo bottle fed horse. He only has 2 modes, firstly on his back feet and secondly his teeth attached to your tits whenever you get close enough. (that is a real life example of one of mine)
The trusting relationship part is fine but these are big powerful animals and, when young especially, not always very respectful of their human.
theories are fine but then there is real life.