GBS, I have friends with major airlines that took 20 years to get a command - and even then they tend not to refer to themselves as captain.
Their employers do refer to them as 'captain' however, having promoted them from First Officer.
All these things are subjective, but IMHO the type of person who thinks they're the 'captain' of a little boat or little plane, and feels the need to buy regalia that indicates they are a captain, almost certainly wouldn't pass a command course.
Too insecure.