Doing minimal research on prohibition since I had no context into what triggered it: "Prohibition also united progressives and revivalists. The temperance movement had popularized the belief that alcohol was the major cause of most personal and social problems and prohibition was seen as the solution to the nation's poverty, crime, violence, and other ills." [0]
You could replace alcohol with firearms and the part about removing them being "solution to the nation's poverty, crime, violence, and other ills". I bet there are a lot of people that would believe that prohibiting firearms would help solve those issues.
Just because laws are not easy to enforce doesn't mean they can't happen. There are still counties in some states that are 'dry'.
[0] https://en.wikipedia.org/wiki/Prohibition_in_the_United_Stat...
I personally would _never_ willingly turn mine in--they're for my and my family's protection and have saved my life before. I am certain many gun owners feels this way as well. Trying to enforce such a rule would be difficult, if not impossible.