The article also has a disclaimer saying the DuPont Rothschild and Sinclair have not been accurately calculated. (Mostly due to reasons I stated earlier, they hide thier wealth and the nature of their industries makes it difficult to determine the value of their assets)

The Rothschilds and others mentioned didnt make the list because the list is based on personal wealth and the value of personal assets. Rockefeller had more value at his peak because he had not only his own liquid assets but also majority stock in the nations top 10 oil companys. Sell all the trucks, railroads, land, refineries, etc of the company add his wealth and then bingo. The Rothschilds and those like them hide their money and also, being bankers, have all their companys money tied up in companies like say, Standard Oil.