Narcotics has always been the biggest earn. But the draconian penalties coupled with the low-brow of trash you deal with in that trade turned most of the smarter guys off it.

Some others dealt ultra carefully and successfully. Made their money and got out safely, reinvesting those profits into legit businesses and more genteel rackets like gambling and shylocking.

But, unfortunately for them, many delved in head first, making it their life's "profession." Invariably, 99% of those who did, ended up behind the eight-ball, one way or another.