Yea it's called "The Iron Law of Prohibition", which mostly has to do with the fact that more potent drugs take up less space per eventual dollar paid by the en

Yea it's called "The Iron Law of Prohibition", which mostly has to do with the fact that more potent drugs take up less space per eventual dollar paid by the end user, and shipping lower volume means dealing with less risk (and thus cost) during transport (risk, of course, being one of the main things that make drugs expensive).