The original post asked if there might be something that INTJs are missing because of personality type. I am almost the opposite of INTJ (ENFP), so I wanted to comment on this because there are some things that stand out to me as I read posts on sites like this. I think that sometimes INTJs can lose the forest for the trees, so to speak, because of a need to adhere to the "right way" to do things, or follow "the plan" that they've laid out. (By the way, I have INTJs in my family and my husband is INFJ.) For instance, I read on here a post from a woman who recently became a millionaire and mentioned that she'd bought new cars and kept them well and for a long time. Somebody said something like, "Hey, new car buying is not MMM," completely missing the point that the woman said she'd just reached millionaire status. Who cares if she didn't get there completely MMM style?? What she did obviously worked. That's what I mean about the forest for the trees. I think that INTJs might miss opportunities that come from being open to a diversity of ways of doing things, and also from networking with real people. Their strength seems to be structure, order, routine, optimization, planning. I think that the liability is that sometimes it can be a little Rain Man-esque when there's a need to switch things mid-stream, invent a new plan on the fly, etc.
I also wanted to comment on some of the posts that talk about how many INTJs are on here because it's a good fit (can be alone with your computer, for example, and not in a crowd). I am guessing that there are a lot of personality types that come and go on sites like this, so these people likely aren't voting on this because they've already gleaned what they needed and are now down at the coffee shop talking about it with their investor friends. If you are a Perceiver, you tend to like change and diversity, so to come and go makes sense. I know that I get inspired on sites like this, but then start thinking about creating a little monthly group in my community where we can get together and trade ideas and inspirations in person. My guess is that INTJs use a forum like this as a main source of their inspiration routine. Thus, it makes sense that many personality types are saving and building their wealth in MMM ways, but just not talking about it online. To come and go has its liability also, however, because there are things that one probably gets from hanging out here for a long time and regularly. Thank goodness for archives :)