Well, given the fact that Prohibition weakened the rule of law throughout the country and to a large amount of money flowing into the pockets of the Mafia, I imagine that people soon knew that it was an unmitigated disaster.
Agreed. Prohibition was partly repealed so that alcohol could be taxed, yes. It was also repealed because it was an unmitigated disaster which never worked and which was doing more damage than good.
For one, it only punished the poorer people. If you were rich, you stocked up on masses of liquor, which I think you could legally drink as I believe prohibition made illegal only sale and purchase and not consumption. If you weren't a Rockefeller or a Senator, you were screwed.
It also never prevented people from drinking, as moonshiners and bootleggers took care of that, and people wanted to drink. And it just made those people criminals, and created organized crime, and allowed Gangster empires to rise as they would never have been able to without prohibition, which in turn corrupted governments, towns, cities, and created violence in the streets of American cities.
Even people who were temperance believers were forced to admit it was a failure, and a bad one at that, which is why when FDR came, the government decided to repeal it.