At a certain level of taxation and regulation, the effects become more or less indistinguishable from prohibition (the Eric Garner story for example).
As to whether or not prohibition works, it depends on what you assume the purpose of it is. If it is to create black markets, then it does work...and black markets serve the purposes of the "system" in many ways.
When the term prohibition is used, most people only think of the history of alcohol prohibition, but we've had prohibition on many substances ongoing since then. The only difference is that it was understood at the time of alcohol prohibition that it required a constitutional amendment...that requirement has long been abandoned.
As to whether or not prohibition works, it depends on what you assume the purpose of it is. If it is to create black markets, then it does work...and black markets serve the purposes of the "system" in many ways.
When the term prohibition is used, most people only think of the history of alcohol prohibition, but we've had prohibition on many substances ongoing since then. The only difference is that it was understood at the time of alcohol prohibition that it required a constitutional amendment...that requirement has long been abandoned.