I don't think any further explanation will suffice, so I will reiterate what I just said.
D&D (and 5e) is the sum total of not just the rules, but the playing community and the norms. The expectations. The tensions between RAW and freeform groups. The expectations of those who want giant set-piece battles ever session with minis, and those who prefer a flowing game with very occasional ToTM combat.
And that's why this never gets anywhere (putting aside, for the second, that this thread was never about 5e). When there are those who discuss the flexibility or "big tent" nature of 5e, they aren't discussing a diversity of outcome, necessarily- D&D is very good at D&D- which is to say, a kind of fantasy that never existed with its own norms that can incorporate anything into it from spaceships to anime-inspirations, because it never bothered to be something more specific. On the other hand, it does allow for a multiplicity of process in order to be D&D; you can have a group get together at lunch and play some diceless 'D&D' or have someone play it as nearly a wargame or have another group incorporate 4e elements and skill challenges into 5e (there are plenty of places to find how to do that if you don't want to do it on your own).
That diversity of process is something that is definitely unusual in most games, which lack the history, community, and norms of D&D- most games expect that you will be playing the game as it is designed.
And that's it. That's the fundamental disconnect between what you are saying, and what others are saying. You keep asking for people to explain things to you in a matter of X (D&D is only good at D&D- what you call a conceptual space and I call diversity of outcome), and people respond by saying, "No, it's actually Y that we're talking about." (That D&D, because of the history, norms, 3PP, community, etc., has a great diversity of process and playing styles that are not encapsulated within the rules qua rules).
This disconnect in what people are discussing underlies a great deal of the disagreement, and not just about D&D. If people don't agree with a priori terminology and theoretical models you are using, they are unlikely to be able to explain things to you in a manner that you will find convincing; however, by the same token, you will be unlikely to convince them.
So if you were to abstract things out a little, and (to avoid jargon) simply state that D&D is better at some things, other games are better at other things- I think there would be broad agreement. But the actual disagreement is something I don't think will ever be resolved- because some people prefer systems that are flexible, hackable, and have large communities and norms regarding them, and others prefer systems that provide for any flexibility within the ruleset qua ruleset, and I doubt that this difference in approach is likely to be bridged.