Hi Sentso, you're right - a lot of excellent and sober musicians come to mind, but many of them spent years drinking or using heavily before cleaning up their act.
I can sort of relate; though I'm not a musician by any stretch of the imagination. At one point in my life, I hung out with a fast and high-living crowd, lots of travel, wine tastings, parties - so much of what we did involved drinking and I could keep up with anyone and then some. Even healthy activities - skiing or hiking, eg - was inevitably followed by hitting a bar or restaurant and getting wasted.
During that time, I actually managed to get sober for almost a year (about 17 years ago) and managed to keep all of my friends, too. Including the two people I shared my house with. I did nothing but white-knuckle it and decided I wouldn't be like those preachy, tiresome AA people** so I told people I was just not drinking now, wringing out the ol' liver for a while, like that. I became the designated driver a lot of times but I tell you it wasn't as much fun being the sober one with a bunch of silly drunks!
That said - I didn't give two craps about what most people thought, so it was no big deal to simply say I wasn't drinking, end of story, because I figured I owed nobody an explanation. I did tell close friends I thought I might be an alcoholic and was giving this sober thing a try. I'd nicely tell obnoxiously pushy people to STFU and NO and that was that.
**I am becoming one of those AA people now, because nothing else worked and my drinking patterns continued to get heavier and much more destructive.