I agree. But they could intentionally be creating an overlap should one of the two fail. Also, the HL cure definitely may not work completely, so the tinnitus therapy could still be relevant. Finally, although I too am of the opinion that nonsomatic T is almost always caused by some type of HL, I believe there are some cases where it is not (e.g. TBI, where the cranial auditory system is affected directly).
So unfortunately imho your statement is based on a viewpoint that is too optimistic
What is NDMA and what is the NDMA hypothesis?