Furthermore, your willingness to buy into the narrative (and others' willingness to also believe it) that by categorizing certain people into stereotypes and assuming that most of these people tend to excel at a particular set of tasks is most likely what limits them from excelling at tasks that lie outside of their respective sets just as much as their true predisposition to not excelling at them.

Saying that any profiling technique has zero predictive value is a very bold claim.

Even one's astrological sign has predictive value: [1]. And yes, this has been scientifically proven.

[1] http://www.medicaldaily.com/how-birth-month-influences-perso...

For example, companies fruitfully extract predictive power from whether a user clicked a link or not. Facebook extracts predictive power from whether users like videos, et cetera. So why shouldn't an elaborate test that was developed to have meaning, not have any predictive power?

There are results that show MBTI has no predictive power against job performance. It has not been tested against any other measure.

That said, MBTI shows bad orthogonality in the factors in its response. This suggests the factors are ill defined.

Could you provide a reference?