You want dangerous substances made legal then think taxing them would benefit society?
For centuries people have made lucritive business by avoiding taxes: It is called smuggling and yes, groups like the Mafia still make money smuggling tobacco and alcohol across state lines today.
The government claims tobacco and alcohol as deadly but cannot resist the money tied to them- That money is more important than peoples' health yet the same government has offices dedicated to ending the use of tobacco and alcohol and offices to subsidize those industries.
You will note that ending Prohibition didn't spell the end to organized crime- The rise of labor unions, the Second World War, government rationing, and taxes actually caused organized crime to expand after the end of Prohibition so legalizing drugs won't make the Cartels go away- They'll produce cheaper, nontaxed products and smuggle those across borders and into states that apply their own taxes.
Don't get me wrong- Government should drop all forms of regulations and taxes. If adults want to kill themselves, I have no problem with it, as long as the government doesn't waste any money keeping these worthless bastards alive.
I don't want the government to have a monopoly on anything- If Bill Gates has enough money to build or buy his own nuclear weapons he should own them. The Second Amendment protects that Right.
If I am able to bodge together my own warheads, I have the right to own or sell them.