Investigation may be a thing to gamers, perhaps not just because of CoC. Maybe the collective unconscious of the hobby has accepted or come to expect mysteries because of how long RPGs had the traditional GM approach, where the GM presumably knew a whole bunch about the world and players had to make rolls or query the GM in order to get information about that fictional world in order to proceed. Take OSR games for example where you have folks talking about a lot of stuff and not as much rolling – if you roll you have probably done something wrong. The game is about investigating mysteries in every room in the dungeon in order to move forward, though the end goal is to gather loot.

I think investigation rules ultimately come down to narrative control. The player asks for information so they can then do things in the world – I need to know what something is in order to know what I can do, for example. Because they have been trained to assume they don’t have much narrative control beyond their own characters (and some folks want it that way). Even when folks are shifting paradigms, we are still living in the context of others that came before