@serendipity1996 is right. Research over the years into treatments for tinnitus have not been well-funded or supported because medical approaches such as TRT were allowed to prevail without question, and so became dogma. Can you imagine telling someone with Crohn's disease or cancer that it's all in their head, they need to reframe their relationship with the condition and that they should just learn to live with it? But this is exactly what happened, and so there was very little financial backing for research into treating tinnitus. It is hardly surprising therefore that that recent long-term study showed no difference between TRT treatment and placebo. If you have had TRT and you've learned to live with tinnitus or your hyperacusis got better, TRT didn't cure you: you got lucky and your body healed in spite of the treatment, which was most likely doing further damage to you.
As far as hearing loss is concerned, cochlea implants have been around for years, but again, these were mostly designed for war veterans or industrial workers who had lost their hearing in the pre health and safety age, so the market was never seen to be big enough.
We now live in a different time. I remember around 2004 or 2005 I was reading an article that said something along the lines of by 2025, some 50% of 30+ year olds will have noticeable hearing loss. I was 14 at the time and I'm coming up to 30 in a few months time. I have had tinnitus for 13 years and hyperacusis for the last 6 months. This article was written around the time iPods and mini mp3 players came out and everyone could own one; it was written around the time mobile phones were becoming the norm and, again, everyone owned one; it was written around the time that PC gaming was also becoming very popular and many kids were wearing headphones.
So what you see is a change in the environment. Not only was the world already noisy as it was with city traffic, construction, bars, restaurants and nightclubs, but the population as a whole was starting to engage in much noisier day-to-day activities that would put its hearing at risk. It was not a surprise therefore that less than a decade later biotech companies and PhD students started to make hearing loss and regenerative hearing an area of interest - precisely because it would become a matter of public interest and therefore one with potential market value. It is not uncommon for researchers to pick their area of study based on their chances of securing funding for their research. Quite sadly, the world revolves around money. All I can say is that I hope now capitalism does its thing and we all, in the coming years (or sooner), end up with the treatments we need to never have to visit this forum again.
Seriously, fuck these conditions. As someone else on here once put it, this journey is for the strong.