The source of the Three Families' wealth is their adrenal synthesis factories, which convert the Republic's processed Quesh venom into precious adrenals. The length of the process depends on the quality of the adrenals required; military grade adrenals take a week or so to produce, while cheaper ones can be created in days.
The Three Families guard the secret of adrenal creation very closely, meaning access to the factories is strictly regulated. All Republic personnel working there have to be carefully vetted and vouched for, and are subject to search without warning by Three Families enforcers. To keep its partnership with the Three Families harmonious, the Republic employs harsh punishments for theft; it is not uncommon for thieves of a single adrenal canister to be jailed and fined the cost of an entire vat.