Ken Burns explains:
The real turning point is the Depression. You say, “OK, we got rid of the fifth largest industry for what reason? We don’t have these jobs that we could use for what reason? And we don’t benefit from this tax revenue for what reason?” Life was so hard in the Depression. We can’t even appreciate it now, even in tough economic times, how bad it was in the Depression. When Roosevelt came in, within a week beer was legal, and the repeal of the amendment went into effect, that is to say alcohol was available, on December 5, 1933. It was almost anticlimactic. It is like, we’ve got to get going with something else more important.
The Dish 