The reason marijuana is still illegal is not because they wouldn't make any money (they could easily tax it). It's because various corporations such as the alcohol corporations are paying the government to keep it illegal. If marijuana is legalized, then people won't drink near as much alcohol, thus, for alcohol to keep getting lots of money, they must sway the government on certain issues. Nowadays the government doesn't control the government, the corporations control the government. Hell, the heads of the corporations ARE the most rich people in the world.