Just because Casso was Underboss to a smaller family, doesn't mean he didn't have his fingers in as many pies...plus, he "could have" demanded a larger percentage of the kick from his underlings. Gravano was Underboss for a very short period of time...obviously he had legitimate construction and demo companies, but Casso had his share as well. Hard to determine. Guys like Accardo and Gambino were on top for so long prior to RICO, if they were smart, could have been worth up to $100 million
A question: when they have interests in construction or other legitimate businesses, do they formally own companies registered to them or do they use front men while they are formally unemployed themselves, like in Italy? For example, Toto' Riina was one of the most powerful mobsters, but formally he was just a peasant without property, what about American mobsters, Casso and Gravano in this case?