I'm 90% convinced that a strong inner monologue tendency develops when a person desires or needs to discuss things with others but can't find anyone willing or able to discuss xyz things, for example say a person grows up in a family or social environment where there is a huge elephant in the room so to speak, they notice it glaringly but everyone around them either acts like it's not real or has a cold silent attitude about it ie acting like it's very taboo to acknowledge it, that person is then much more likely to develop a strong inner monologue to meet the need of socially processing things that everyone else seems to either dissociate from or willfully ignore, so it makes a LOT of sense that many people branded as "conspiracy theorists" would have a strong inner monologue, ie people who hone in on things that most people don't want to acknowledge let alone discuss