You've heard from those who got out - I can tell you what it was like to stay.
I never had the guts to leave. My husband's descent was not so dramatic. It was easier, maybe to think that things would not get worse (but they did). For the first few years we were married, he was employed, and although I realized he had a problem, I doubt many other people did. He was employed. But he did get an OUI early on, and there were times he called in sick because he was hungover.
His employer was bought out by another company, and he took advantage of this period of unemplyment to just drink - a lot. He didn't look for work at all. I had to really push him, as the end of the payments drew near, to apply for anything. He found a job --just-- before his unemployment ran out. It was a job he hated, but he did it. Unfortunately, now his drinking consumed more of his attention and became a priority. That meant he was doing zero to find something he DID like. Toward the end of this job, his drinking was out of control: he was irritable in the morning, hungover often. His job offered flex time, so there was about a two hour window for going in in the morning, but he wasn't putting in the hours, some days he was gone barely six hours. His supervisor tried to salvage the situation, but admitted that not only was AH only there about 30 hours a week, even when he was at work, he was away form his desk so much his colleagues had a hard time contacting him when they needed him. He was fired after about twelve years.
He had two more jobs after that, fired after a year or two at each one, and of course, stretches of unemployment, (The employers didn't charge him with insubordination or anything, and didn't dispute his claim in any way, so yes, he was collecting.) And although our home was paid for (no mortgage) the unemployment didn't cover his half of the bills, once his beer and cigarettes were purchased. (I am only guessing, but I think he was drinking between 12 and 18 beers a day.) In fact, he was withdrawing money from his retirement account which was increasing our taxes. He didn't tell me, our tax preparer told me.
For me it was just more and more depressing, until I started to detach. AH didn't want to go anywhere or do anything that would interfere with getting a drink. He was irritable and unhappy and argumentative most of the time. Eventually, I pretty much stopped talking to him at all, once I realized that often he was just picking fights. On the occasions I agreed with him, he would somehow switch sides so we were still at odds. Most of my verbalizations were just murmuring "Mmmhmm" to whatever he said. AH was diagnosed with cancer about the time I decided enough was enough - literally the day I decided to get my act together and make a plan to leave. He died about eight weeks later.
I often say I miss the man I married, but that person started disappearing long before he died. We were lucky that of the two OUIs he had, neither was an accident that took a life or hurt anyone. AH dodged a bullet on the second one: our state has much harsher punishments for someone who accrues two OUis within ten years, and he had just barely passed the ten-year mark when he got the second.
If I could talk to my 27-year-old self, I would say, "Yes, he's brilliant and charismatic, yes, he adores you, but there will be others, I promise." Starting over single at fifty-something is not as much fun as dating when I was in my twenties.(unless ruminating on how so many have come so undone is a dream come true for you) On the plus side, I see others for what they are now, not for the 'potential.'