"Significant in Jung's theory is that "type preferences" are inborn and not socially constructed through interaction with the parents, family culture and other external influences. Even so, the individual is impacted in the quality and strength of the development in his or her preferences. Nature and nurture are both at play. A supportive environment will facilitate inborn preference development; a contrary environment will impede or retard their natural development."
http://www.newworldencyclopedia.org/entry/Carl_Jung#The_Collective_Unconscious
In short: A leopard doesn't change their spots so easily.
Although life experience might magnify or diminish innate traits, and shadow traits might become more observable, the inborn type, essentially does not change.
+ TiC, if subscribing to Jung's typological system, one ought to recognize and understand the roots and his underlying theory behind the system.
An example of nurture's influence on a type:
I use Ni as a #2 function in place of Ne often.
Ti > [Ne/Ni] > Si > [Fe/Fi]
This stack of mine ^ points to overused shadow function.
Growing up with and heavily interacting with a typical and dominant INTJ very likely created this.
Although, overwhelmingly, tests find me to be INTP, as a consequence of heavily using Ni, I've also variably tested as INTJ (ili/INTp) in some function (not MBTI dichotomy) based tests (even despite the fact that I lead with Ti and use Te
significantly less).
-I expect that, in others, a strong nurture influence could modify use of functions so much that it leads to type confusion.
I illustrated before somewhere; typology works similarly to taxonomy.
The types already exist in nature, and now a categorization system exists to explain the differences and similarities between those types.
-Please also TiC that Jungian typology is simply a
theory.