I am an ISTP personality. My preparation is heavy on the skill side. Sometimes I think it would be interesting to have a certain skill an often I end up to learn it just for fun. The range goes from cooking, baking sourdough bread over amateur radio and lockpicking to reloading, shooting muzzle loaders, CAS, hunting, fishing and extended first aid skills. New skills also require new toys badly needed equipment.
Somehow having some supplies seems just natural.
So in conclusion the driving force behind my preparedness might be a personality flaw.