There was an entire underground culture and supply chain for alcohol consumption during prohibition. What happened to this supply chain once prohibition ended? Were they simply out of business? How did the underground clubs adapt?
I can't speak for the nation as a whole, but here in Cincinnati many of the speakasies did go legit; a really good example is The Syndicate restaurant:
It is part of NASCAR canon that the organization was founded around bootleggers getting together and racing each other. This was in the 50's and not so much Prohibition Era.
Most of them went back to doing before prohibition ended - their day jobs. most bootlegging was a late night cover of darkness deal.