There's another reason which you didn't mention. It's not personality, and it's not that I feel terrible after a few drinks. I drink very little because the following [1] is incomprehensible to me:
Alcohol – Euphoria has been reported during the
first 10–15 minutes of alcohol consumption.
I have gotten very drunk and yet not experienced euphoria or anything similar. To be sure, alcohol has physical effects on me (e.g. impairment of judgement and impairment of coordination). But it just doesn't do anything mental, for better or worse. I'd bet that many/most of the 60% or so of people that have less than one drink a week fall in that category. I.e. to us alcohol is "meh".I'd much rather have chocolate or sugar than alcohol. E.g. I like Grand Marnier, but that's because it has a pleasant sweet taste, not because it has alcohol. I'll drink a few beers a year, but that's because I'm doing something social, like watching a football game with friends.
so just like you said, this is why it's so hard for problem drinkers to cut down. it's just a whole different experience than a person who has a couple and then feels dizzy and wants to sit down.
I'm not saying there isn't a slippery slope, but I personally cannot imagine my life without at least some alcohol. I assume for the case of someone where their (excessive) alcohol intake has a huge negative impact on their life, zero alcohol sounds like a much better deal than drinking a lot.
But I still question the accepted "fact" that this is really a fixed "personality" thing. We humans have extraordinary brains and have the power to -- possibly with help -- change a lot of things about our personality and emotional state. It seems hard to believe that "once an alcoholic, always an alcoholic" is actually absolutely true.
but look at you - 2-3 occasions in your life - the people who have problems cutting down are doing that 2-3 times a week and are completely functional. it's a completely different personality type.
the bottom line is, for a lot of people, it's a LOT easier to stop than to 'cut down'. this isn't a magical premise. in fact i think it makes a lot of sense. similarly, for a lot of people, stopping is impossible. and that's how you get numbers like 74 drinks a week which sounds fucking ludicrous at first blush, but is in fact quite doable.
That's what addiction is. It's like asking why someone with OCD can't simply not wash their hands. It's mind bending to even imagine for someone who hasn't had that experience. I've dealt with obsession and compulsion at times in my life (not as a disorder), and I know how hard it is for me to modify habits and fixations. True addiction is some next level shit.
These are, however, all things that have been extensively studied and documented and affect millions of people. It's not necessary for you to be able to really get inside the head of an alcoholic, but that shouldn't keep you from accepting that this is simply how things are for some people.
heavy drinkers find drinking intensely enjoyable - and (subtle difference here...) not displeasurable in any way whatsoever until hangover/puke. if you aren't the kind of person who's ever drank 15+ drinks in a single night, you just have no ability to comprehend this. it's not within your realm of understanding - your personality is just completely different. or your brain chemistry is such that after 3-4 drinks, you feel terrible.
if so, be thankful.