One thing that's not mentioned here, but something that I took away from Wolfram's obituary of Lenat (https://writings.stephenwolfram.com/2023/09/remembering-doug...) was that Lenat was very easily distracted ("Could we somehow usefully connect [Wolfram|Alpha and the Wolfram Language] to CYC? ... But when I was at SXSW the next year Doug had something else he wanted to show me. It was a math education game.").
My armchair diagnosis is untreated ADHD. He might have had had discussing the internals of CYC on his todo list since its first prototype, but the draft was never ready.