I agree with this, but we've got multiple drugs and devices in the research pipeline for tinnitus, as well as a wider spectrum of drugs and therapies aimed at reversing hearing loss. That doesn't mean any of these approaches will go anywhere, per se, but it does mean that rich capitalists see this as a potential vector for becoming richer.
You're totally right, but unfortunately there are many conditions that reap greater rewards for those in the medical field. Diseases that affect a larger amount of the population and that are, when it comes down to it easier to understand, are a safer investment. During my course, we've covered most diseases and all tinnitus was given was 'yeah we don't understand it, there's no treatment, and it sucks to have it. Now back to cancer, diabetes, COPD etc...'. I think if people within the field gave tinnitus research a second thought they'd see there's actually a lot of money to be made in it, but unfortunately most of them think there's bigger fish to fry.