The catch in all this is that pilot training - all the way up to airline pilots - does not include any kind of character profiling and psychological testing such as might be implied in the above.
I'd think that austronauts were/are chosen with plenty of such testing, and I would be amazed if the RAF did not use psychological profiling for jet pilots, and anyway it is becoming pretty standard in big-company recruitment, but to become an airline pilot you only need to pass 14 exams and grind through endless training which is pretty well structured. To become a private pilot you need a lot less of that. But anybody with an IQ of more than 50 and with sufficient determination (and funding, perhaps) will make it eventually - despite the alleged establishment efforts to use the IR as a gatekeeper to stop undesirables from getting airline jobs
Back to private flying, it would be wrong to use psychological profiling as a basis for a PPL award, not because it would not improve safety (it
would IMHO be the only way to improve safety) but because the State has no business in dictating individual attitude to risk. If one applied this to pilots, for every life safed one would save a 100 lives by applying it to car licenses.