[adventured]

Bill Gates probably already took that title. He'll have generated a likely $150 billion in total wealth by the time he's done (stands at around $115 billion now; $87 billion per Bloomberg's rankings plus around $30b+ given to the foundation so far). He built a monopoly at the core of the most lucrative boom industry of his day (computing and software). Similar reputations, similar drive and ambition, similar behaviors under anti-trust questioning, similar response to give his wealth away after stepping away from the business, and so on. Interestingly however, Gates was far more prone at emotional outbursts and getting upset, Rockefeller was extremely contained by comparison.

As someone else noted, Bezos might follow along with Gates, but it appears Bezos is more like Sam Walton than a Rockefeller. Walmart sprawled into numerous other categories, attempting to perpetually find new ways to make money at the edges of its empire; Walmart is a hyper low margin business, built on low prices and high efficiency; both Sam Walton and Bezos retained very large stakes in their businesses despite the size; both kept fundamental control. Amazon has no serious monopoly category however, and they have a comparatively weak cash generation capability (AWS is spitting off some nice operating income, but it pales in comparison to the very high margin cash spigot that Windows was).