Why do you think cannabis is really illegal?

I was thinking the other day why might cannabis really be illegal. From different philosophical perceptions. These are just my opinions on the subject correct me if I'm wrong:

1. It's easy to blame for being a gateway drug because it's so widely available. I think cannabis makes you curious to what it feels like to be on other drugs, but not giving you the motivation to actually do it. I think while being high and watching documentaries on different drugs and their effects is sufficient information and allows the THC to play the closes to having "effects" digitally. I think if you let Cannabis lead you to other hard drugs, you had an issue to begin with before drugs all together. Again... just opinion.
2. When being high, and losing your ego, some people experience seeing the world from a different perspective. They see the true important reality on what's good and bad. Futuremore, back to thinking why it might really be illegal, is because some of the things were able to see ("removing the vail") might break us from being in formation social control? I know for a fact since smoking cannabis, I question everything now. And it could also make you see how messed up the world is... again this can be good or bad.
3. Being that it's so widely available, government is able to capitalize on it. (Prisons, job security..etc) So maybe why they are so hesitant to federally legalize, it's because many people in criminal justice would lose their jobs?

If any one else has interesting theories to why cannabis is really illegal, please share!