But the key component was curiosity. I've always wondered what Gygax's works were like after he was ousted from TSR and worked on projects unrelated to D&D, but I did not own any until now.
In my post the other day about old school play style in D&D 5th Edition, I made an off-the-cuff remark that got some attention from a few people in the comments. It read:
"While Gary Gygax and Dave Arneson were both incredible visionaries, it's clear from the rules that neither of them were outstanding game designers. AD&D was a hot mess of mismatched and inconsistent rules. Whether that was more due to Gary's influence than Dave's is a topic for another day."
In the comments I later clarified with the following:
But they didn't know how to organize their thoughts into manuals that made clear how to play the game. [...] That's what I mean by "game designers". It's more than just making up the rules... It's also creating a presentation that others can easily follow, and those old books just aren't that good at that.
They are still in the pantheon of gaming gods... but their thoughts could really have used a good editor who understood training manuals. :)
Aside from the evidence in the 0D&D and AD&D rule books, the other part of this statement resulted from my recent forays into the Dangerous Journeys books (which also have lead me to believe that Gygax, not Arneson, is largely responsible for the convoluted systems within AD&D... but I'm getting ahead of myself).