I guess there is two sides to the coin on dope, for various health, family and criminal reasons I haven't even seen the stuff in years. I won't touch the stuff because I'm already lazy and I eat too much without the munchies
What I will say is Australia has enacted laws where if a criminal "drug dealer" is living the high life because of his illegal earnings, they can have the taxation office investigate their lifestyle and assets and tax them on what is classed as unclaimed income. Some famous crims have got $2 mil bills from the tax office with gaol (jail) if they don't pay.
So there are ways of making the crims pay for their crime without the hard evidence of doing the crime.