1. Alcohol is deeply embedded in human culture, to get a significant portion of society to stop using it would be like trying to get people to stop eating bread or to stop having sex. It would be expensive and unproductive to enforce.

2. Alcohol is easy, though more dangerous, to make. To prohibit it would be to turn people towards more-dangerous moonshine.

3. Relatively speaking, alcohol's health effects aren't that bad; it's poison, but it's only very mild poison. Overindulging on alcohol once mostly leads to a hangover, it's difficult to drink enough alcohol to kill yourself and it starts to get unpleasant before you reach that point. The real dangers of alcohol seem to come with chronic use.

4. Alcohol is not extremely addictive. It seems most people can somewhat regularly partake without becoming alcoholics. In my understanding most addictive drugs won't get you hooked the very first time you try them, but trying them a few times is usually all it takes. Anecdotally, having used both, sometimes in excess, I find it much easier to resist a drink than nicotine.

If you pair these with the other harms and expenses of general drug prohibition (organized crime, disproportionate criminalization of minorities, etc) it becomes very hard to justify the prohibition of alcohol, in my mind.

Some of those things apply to tobacco too but to a lesser degree, so the case for illegalizing it might have some legs, although I suspect it's not worth it either. I might argue that burning tobacco products, specifically, should be illegalized due to the fact that there are several known, practical, and less destructive nicotine delivery methods. Lozenges, patches, and vapes work, and so far seem to be much less catastrophic for one's health. It's not clear to me that you'd get murderous tobacco cartels who lace their product with fentanyl.