You're right. The example does not require exclusivity, but you're missing the point (or at least didn't directly address it). My point was not to illustrate individual things that can only be done if exclusive. That's impossible. You'd never find something. Depending on what poly people choose to spend their time on, they could always do some of the same individual things that the mono relationships are doing. My point is the sum total of all of those things happening the majority of the time cannot be replicated. That's the fundamental difference. So it would never be about pointing to some specific thing that mono people can do which poly people could never do. Arguably the whole point of being poly is the freedom to do anything. The point is that the level of understanding and individual focused commitment created in a mono relationship cannot be replicated in a poly relationship for reasons of physics.
It's interesting what you gain from relating the experiences, and of course all humans gain something from some form of stories. However we are physical creatures. Your brain rewires in accordance with what you interact with. A great deal of your self and perception is based on stored memories. Love I think is separate from that. It's an emotional state or a state of feeling. It may also be an ethical state for some people where they define love by the ability/desire to make sacrifices. However from a realistic standpoint a mature and committed mono partner will always end up knowing their partner better than a mature and committed poly partner. I don't think there's any way around that. I agree with (and I'm too lazy to scroll back and find out) the person who said that not all monos will be willing to go deep and not all polys will be willing to go wide. I think that's very accurate. However in the instance where you had two polys willing to go deep and wide currently in multiple relationships, they cannot achieve the same depth of understanding and knowledge of the other person as two monos willing to go deep and not going wide. That has nothing to do with how it feels to the individual. It's just the practical reality of it.
Again, to bring the argument out to other situations, a particle physicist must be constantly on top of her field. She has to be reading journal articles, constantly tracking the latest experiments, and also consistently researching and publishing her own work. If she were to try to keep up a career in genetic engineering as well, she would be in a constant battle to keep up with pioneering research in both fields as well as her own. She might be brilliant, but I don't think there's a case to be made that someone equally brilliant focused on one field would not achieve a greater understanding of it and more research within it than she would.
To bring that back to the relationships, removing a certain amount of the complexity (what I've been referring to as depth though the word has unfortunate connotations) from it is fine. That's what I mean when I say you could replicate any of the individual experiences but not all of them. That's removing part of the complexity. Also to hear a summary of the experience later does remove some of the complexity of actually having that experience yourself. Thus no one who reads adventure books has a portrait hanging in the Royal Geographic Society. The experience of the story is an experience and even a shared one, but it does not hold the same level of complexity as the actually shared experience. So you can share any experiences with a poly partner that you want to, but you can't share all of the experiences that mono partners do. Due to the way we're wired and the boundaries of linear time, that means mono partners will end up with a greater level of depth and complexity in their relationship than poly partners. A sacrifice that I think is made for the greater level of complexity in one's individual life where the poly individual has multiple relationships and thus arguably a more complex individual exploration than the mono partner.
I think the choice for poly versus mono comes down to complex individual exploration versus complex relationship exploration. I use the word individual not in the sense that the mono relationship does not enhance the life of the individual. Rather what I'm saying is that the poly person is choosing to explore their responses to a variety of people in relationships, intimate connections, and/or sexual experiences. This is in line with more of an individualistic philosophy thus the usage of the word. The mono person finds more to be gained, as I've said before, from the complete exploration of the single partner and gives up other explorations they could have of most levels of outside relationship/intimate/sexual connections in order to do so. I'd also like to note again for posterity that I am not saying these are black and white. There is a spectrum. Polyfidelity with a minimal number of people would seem to provide a much greater opportunity for relationship complexity than a totally open and individualistic polyamory. I simply think that mono and totally open poly represent the ends of the spectrum in that sense.