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My personal position would be that playing Ironsworn in co-op mode is no farther removed from the roots of the game than a game like Fifth Edition that calls the DM a lead storyteller. Especially if play involves being led through that DM's linear plots. I would call both worthy descendants and part of the greater D&D tradition. Some of the people I play OSR games would call neither worthy of that mantle,
In my experience and opinion, the fundamental play loop of D&D and most roleplaying games is the one between the DM & player(s).
The one where one person knows (with supplemental improvisation and possibly procedural generation) the details of the world, and acts as the eyes, ears, and cast of thousands for the other people in the game, who inhabit the roles of characters and make decisions for those characters.
DM describes situation, players ask questions, choose actions, DM makes judgements, resolves actions. Repeat.
This is what I was referring to earlier when I mentioned, "D&D as described in the rulebooks".
You can roleplay in other ways, but this is the baseline essence of D&D and most other tabletop RPGs. You can sort-of play D&D solo using a module authored for that, or purely procedural generation, but to my mind doing so is a far greater rules departure than any edition change D&D has ever had. In terms of how we play and what the game IS, OD&D and 4E are more akin to one another than 1st ed AD&D and someone using the 1st Ed random dungeon rules* for solo play. Despite the vast majority of text being identical.
Perhaps this is part of my OSR or just OS sensibilities.
I'm not saying co-operative creation /collaborative storytelling games are bad. If they're fun and a group enjoys them then I would agree that they are worthy descendents.
