Any new drug discovered is either owned and controlled by a pharmaceutical company or it's outlawed. This is living in a “free society"!
The fact that you have to go though the medical establishment to get hold of the legal drugs makes them unattractive or out of reach to most people who don't have a serious medical condition. After all, you don't need to be sick to benefit from a psychedelic! But psychedelics are outlawed. Heaven forbid you should gain an alternative view on life through ingesting a physical substance! The sky might fall in!
Why there is a war against alternative states of consciousness facilitated through psychedelics is not entirely clear. Whether there is a fear among the ruling elite that people broadening their mind through psychedelics makes them harder to control, I don't know. It is also argued that purveyors of existing legal drugs pressure governments to outlaw competing drugs to protect their profits. This seems a reasonable argument and shows how vested interests can work against the freedom and well-being of the people.
See also: Why I am against the drug war