I think the answer is "passion". People remember such details in a specific field because they have a passion for it. The same person remembering techniques use

I think the answer is "passion". People remember such details in a specific field because they have a passion for it. The same person remembering techniques used in movie making probably know very little metallurgy. Most people find some topics that just resonate with them and things just "stick" better. It's hard to force it and if you lack that "perfect fit" (or an incredible memory) those details will still be lost once you put the book down. You'll still have the broad strokes which is still very interesting knowledge to have in a conversation.