Honestly, tinnitus seems like the cost of doing business for many musicians. My bandmate has it, and he has no problems with it whatsoever. He even pokes fun at me for being so careful with my ears, so I make fun of his hearing loss. It is actually funny, I cover my ears and say he is too loud and he shouts "
WHAT?" back at me. This is all done in jest of course.
I am on another forum for bass players and made a thread asking about what people there do for tinnitus. Within a few hours I had many responses. Many of them have severe chronic tinnitus and have no problems. They do not hear it over the music, so it is not a concern for them.
Link to that thread:
https://www.talkbass.com/threads/tinnitus-who-has-it-for-how-long-and-how-do-you-cope.1202831/
I also do not see Brian Johnson as the type of person to wear earplugs, avoid stimulants, avoid alcohol, and make sure that he gets enough sleep to make sure his hearing stays sharp. I am sure his case is one of extreme abuse over many years while being extremely reckless. However, I am no AC/DC buff and I have no idea how Johnson actually lived his life.
But concerning the "you forget about it in just a week..." comment, There are some people out there where tinnitus is simply not a concern for them. My grandfather has horribly loud tinnitus, the only thing he does not hear it over are his guns or power tools. A friend around my age has loud tinnitus as well and has no grievances over it. Many people in my life that enjoy loud music have had tinnitus for years and it has never been a concern for them. I know that many people on here suffer everyday with this, so it does seem crazy for people to have severe damage to their ears and continue on normally. But, I am friends with these people so I know it is possible
That being said, I am not trying to "cheapen" anyone's personal struggles. I am just illustrating that it is different for everyone and continuing a normal life, a loud life even, is possible. But, like Brian Johnson has shown us (once again I am just assuming he has not protected his hearing), by not taking the right precautions with your hearing, no amount of positive attitude will save your ears.