It's not like the Prohibition was the first or the last such attempt. The one I'm personally familiar with was Gorbachev's anti-alcohol campaign. It was also beneficial on paper, with statistically significant improvements in average health etc. But it was similarly flouted in practice. My family lived in an apartment in panel housing at the time, and if you went out onto the balcony and looked around, every balcony around you had some kind of glass flask or jar brewing fruit wine.

The question you should be asking wrt South Africa is how they're enforcing the ban on sales - because people will sell regardless. The general problem with any kind of ban that goes against what a significant part of the society enjoys is that it either goes most unenforced, weakening the rule of law in general; or is mostly enforced, and then you end up ruining numerous lives by running them through the law enforcement grinder.