Diverted drugs become black market drugs. I'm sure the Mexicans are getting ultra pure fentanyl or being trained to make the pure shit from precursors. Somehow most of it ends up being stomped on by the time it reaches the consumer. That is to say just because it was pure when the junky got it, doesn't mean it was accurately represented to the end user or altered along the way. Black market diversion from treatment facilities seems non-ideal.