This theory of yours seems entirely plausible. Prior to November 2020, for the last 6 years or so, I had what I would call a "quiet" high pitched tinnitus on my left side where I would not notice it unless I was specifically listening for it and the room was VERY quiet. I could increase the tinnitus just by clenching my teeth together. That's how I could gauge how bad it was - I would compare clenching teeth to no clenching of teeth, and would always be satisfied that the tinnitus was still the same "quiet" volume in my head. Entirely manageable and not intrusive at all.
Well, about a month ago I experienced a loud traumatic event - my ears felt full for 3 or 4 days, I thought I came down with a sinus infection or something. I had no idea the fullness in my ear, the dampening of all sounds was related to hearing loss. Boy, was I in for a nice surprise about 4 to 7 days later... I can't be sure of the timeline... it just started up late one night and has not gone away... now I have it in BOTH ears, about 2x louder than before and ALWAYS noticeable, even when talking... it's driving me up the wall. Now it's the SAME loudness as when I clench my teeth, but at a slightly different frequency (that's the only way I can tell the sounds apart). I have to literally always be doing something, which is exhausting, in order to try and forget about it. Thoughts of hanging myself now cross my mind, it's torture. On a scale of 1 to 10 prior to the loud event, the tinnitus was perhaps a 1, maybe 2 out of 10. Now it's in the 6 to 7 range of severity, as it has crossed over to both ears, with varying frequency and intensity and I can always hear it.
Perhaps there are some interesting points I can make about my particular case. I lost some high frequency hair cells in my teens from listening to headphones and hard rock too much. I remember my ears would feel hot and numb for 20 minutes or so after listening for prolonged periods (45 minutes to 1 hour). I never had any tinnitus (yet).
Then as I grew older my stress levels increased and I didn't sleep very well - my sleep/wake cycles were all messed up for nearly a decade. I didn't listen to headphones as much anymore, BUT I took dance lessons for years, and wore ear plugs for perhaps 70% of the time (when I remembered them) - the other 30% of the time I would take some chewing gum and stick it in my ears so they didn't hurt. Hard to find earplugs at 1am.
Thinking back to when I was a child my ears were always super sensitive to loud sounds... the school bell would make my ears hurt and I would have to cover my ears. I was born premature by 4 weeks. Already seem to be setting myself up for tinnitus while in an incubator in the 1970's.
Fast forward to my mid-forties (2015) and tinnitus starts to creep into my left ear. I am now careful to wear earplugs everywhere I go - theme park, concerts, outdoor events with big speakers... I had to wear earplugs around my children as well. Ear plugs at the local park. I could not take the pain of loud sounds - anything over 90 dB (I measured it) and it's as if my hearing clipped and plugged up. Hyperacusis? I guess so. I've had it for so long, I actually thought it was normal for everyone to feel the pain of loud sounds. Boy was I stupid. I never asked anyone about it.
Fast forward to November 2020, all it took was ONE loud event, no ear plugs, and boom... my auditory system gets taken over the edge... almost like a cytokine storm... Now what's very interesting is that the loud event was very low frequency... enough to shock the cilia in my ears... so it most likely killed cilia that were already on the verge of dying within the next 10 years... but this noise just accelerated their death... that's what I think. Or I just ended up killing more hair fibers. Can fibers partially work? Who knows.
The way I see it - since I already had some hearing loss... regardless of how little... plus mild tinnitus already... plus the added stresses in life... plus a poor diet and lack of exercise... I basically set my neurological system up for failure... it was not resilient enough to cope with adverse auditory events. I also suffered from joint pains, 10 year old injuries would still hurt, small injuries would take forever to heal or not heal at all, and nobody could figure out why. Medical establishment was useless. I suffered pains all over my body.
I bet restoring even a few of my missing hair cells would reduce the tinnitus back to some manageable level... I will take 10% to 20% reduction any day over nothing. When I look at that graph you posted, I see myself in the red line... and I believe I can get back to the green line. That would be a miracle. I would cut off my little finger if that's all it took.