“Yes, it can come in by ship, boat, airplane. But it is harder to actually infiltrate large numbers of people in that mode.”
We’re talking about infiltrating drugs, not people. Still, even if it becomes harder to bring the drugs over, the drugs just fetch a higher price, which means more profits, and a greater incentive for black marketeers to deal in them. It’s a economic feedback loop that will never be stopped by attacking the suppliers.
I don’t have your Malthusian perspective on the futility of ending the drug traffic.