Prohibition Era?

The films takes place and, most importantly, was produced during the Prohibition Era, yet the movie features a considerably amount of drinking. Since actual consumption at home was not banned (not sure about the party), what I find striking are the street scenes where the Millionaire is clearly drunk.

Sure there were speakeasies, but the whole point was discretion. How could a movie portray a man getting drunk in the city*? Prohibition was a failure as it never stopped alcohol consumption, but was it so evident?

*It is never actually shown how he gets drunk, but it is fairly easy to assume it isn't at home, therefore he would have had to buy the drinks somewhere, which was prohibited.