Ivy don't forget about the Uboats and Japan taking over China and southeast Asia. The other families did have connections, but had to go through Detroit when access was scares. Lucchese and Dragna families had some balls since they stole from military bases. You really have admire that move, since it would have cost a bullet by the sentry.
It wouldn’t surprise me if these factors during the war affected drug supplies. But why did it affect the NY and other families but not Detroit? I can imagine families going to Detroit when it had a supply but can also see the reverse happening depending on whoever had drugs to sell at a given time.
So not only are you saying Detroit was the biggest family in the drug trade from the 1930s to the 1950s, you're also saying they were the only ones with direct drug connections for several years. I see no convincing evidence for any of this.
