"The biggest income source for any Family is ,and always will be,gambling and loansharking"
The biggest or the most consistent and long lasting? It seems that there have been very profitable, if temporary, rackets in the past like the (already mentioned) gas tax scam, drug wholesaling, and, of course, prohibition era bootlegging.
Also, if Paul Castellano was not killed he would have been convicted in the Commission Case (like the heads of all the other NYC families). I imagine that he would have chosen a more competent successor though.
By biggest, I meant most important in terms of consistent day-to-day income. The revenues generated by the gambling/loansharking are what keeps the rank and file guys earning and kicking up. The money also provides a lot of clean graft for police and political payoffs to protect other rackets.
Many temporary scams do generate huge profits while they last,but gambling/shylocking is almost like Social Security for Mafia Families. They know that no matter how business changes,they have steady,guaranteed money coming in.
