I’ve only just stumbled across this old thread but thought it worth adding my tuppence worth of understanding.
DA was running Blackmoor as a distant adjunct to GG’s Chainmail fantasy campaign (though with the addition of the Strategos ‘active referee’). GG had heard interesting stories about the Blackmoor group’s activities (probably the ‘skirmish level’ exploration of the dungeons below the ransacked castle) and invited DA to visit and elaborate on them. David Megarry accompanied DA because he wanted to see whether GG could help produce a boardgame he had developed inspired by the Blackmoor explorations – Dungeon!
GA was very taken with Dungeon! but realised that it could take some time to get the finances together to put it into commercial production. DA’s campaign was a little more difficult to explain, given that the players’ roles covered the strategic, tactical and individual level conflicts (along with the Strategos mind set) and he didn’t have the necessary range of participants with him to demonstrate the full scope of it, so he led GA through the essence of the dungeon exploration experience. GA saw potential in replicating this experience commercially.
However, GA alighted upon the idea that by stripping out the wider Blackmoor campaign he could potentially produce a ruleset that would replicate the Dungeon! game but with a much reduced, upfront production cost. By removing the exploring characters’ relationship with the surrounding world (the Blackmoor characters were, in part, seeking loot to bolster their nations military treasuries) GA created the game of murder hobos with a rule system, rather a system to encourage meaningful rulings, that restricted the active participation of the DM.
One can see why DA was less than fully enamoured with GA’s ‘product’ and recognise the value of exploring the development history of roleplaying to appreciate the approaches abandoned in the name of commerce that could foster a more engaging relationship around the table.