It seems to me that this could be equally profitable compared to street drugs if you take the inflated price for common prescription medicine and health care in the US into account. If you source prescription medicine from let’s say Canada or Mexico to undercut the official street prices in the US your risk of getting cought or run into trouble with law enforcement or rival gangs seems much lower. Also neighbors would not call the police on a guy that sources cheap insulin for the old guy living next door, or what am I missing?
Old people find it harder to get to the shady alleys, and look suspicious at the schoolyard.