Same reason the field of behavioral psychology gets new names and explanations for the same concepts every year: It is not an exact science, and there are very

Same reason the field of behavioral psychology gets new names and explanations for the same concepts every year: It is not an exact science, and there are very few (if any?) first principles that everyone can agree on. All we have are fuzzy concepts that require interpretation and constant refinement, and of course everyone's interpretation and method of refinement will differ. The laws of thermodynamics don't need to be rehashed every year by some owner of a verified Twitter account. Marketing lacks that kind of foundation.