While waiting for funding for scientific research towards stuttering ( which will come in decades , very slowly , very biased and very incrementally) I will focus on what works practically and for most stutterers. No body argued u that neurological and genetic origin IS real , but what matters in daily life is how manageable and how functional can u become . And the majority of that in the last 40 years john harrison and tim Mackesey observed that the majority of that work can happen when u work on speech as a multi layered approach , majority is psychological ;u said it urself anxiety affects frequency so if remove and desensitize anxiety what remains is some vague and very negligible dysfluencies ( maybe more than the general population but that doesnt matter if it doest affect the person who stutters and their functionality in life. As a scientist in training myself, sciece is essential but that doesnt mean that science is complete or not flawed or biased or heavily influenced by what is funded and what is not.