Can we say that the more knowledge/experience, more theorist the learner tends to be. Is there any other factor responsible for changing the learning style of a single user?
sure, learning styles change with learning experience from more or less unstructured to structured learning. A simple example: A child before school may learn very different to the same child when going to high school. The pre-school learning process is much more determined from try and error. Later on, learning gets to be a systematic/structured process (not always but at least when formally learning). Learning undergoes an educational process ... learning needs to be learned.
I would guess that even informal learning changes after having learned strategies on how to successfully learn.
If you take the position that learning styles is fixed, then it doesn't matter what interventions are used, the learning style with remain the same. However, I don't buy this argument because people change vocation and have to learn new ways of doing thing that may require an entirely different kind of learning style. The same is true for persons who have lost a limb or have gotten ill, they must learn different ways of survival which may include harness laten ways of learning.