Well, one even that could happen to implement the continued existence is the actions of the Supreme Court during the period. Try to imagine, using the "state's rights model" applied to the issue of segregation is applied. The idea is that try to imagine that the Supreme Court rules that due to the 10th Amendment, the state governments are on a case by case basis allowed to create municiplaities (ATL's "wet cities") wherein drinking laws are not to be enforced. The only proviso is that in line with the 18th Amendment, all interstate transport is prohibited. So cities like New York, San Francisco, Los Angeles, San Diego, Chicago, Milwaukee, and Cincinnati are allowed to brew and distribute drinks in their appointed municipalities. Also their is the whole "decriminalization" movement (see Berkeley, California), similar to marijuana distribution could have been applied to alcohol, wherein the main tool of punishment is municpial fines (c.$75) and heavier fines for sale and distribution (c$250). As such, most persons charged simply pay a simple fine rather than face any jail time.