Why isn't Marijuana legalized?

I don't get it either. It's a million times safer than nicotine or alcohol. Billions of dollars a year are wasted imprisoning harmless hippies for growing and possessing it. Legalizing it would stimulate the economy and put the dangerous drug dealers out of business. And I also think that legalizing it would change its 'gateway drug' status. If you could grow pot in your backyard or buy it at the supermarket instead of from a dirty drug dealer who also peddles more dangerous drugs it probably wouldn't be much of a gateway drug anymore. Another thing to consider is that pot is also a medicinal herb. Natural, inexpensive and effective it's probably the best thing that a cancer patient or a chronic pain sufferer can take for relief. Makes me wonder if the pharmaceutical companies have had a hand in keeping it illegal. I'm sure they'd lose money if people could use pot instead of paying for their synthetic and expensive alternatives.