The wealth gap hinges on valuation methodology and inflation adjustment timing. Irénée's $3.8B figure represents peak asset value of the DuPont enterprise in today's dollars, while Rockefeller's $340M is his personal liquid net worth adjusted to 1913 purchasing power—apples and oranges. If we adjusted Rockefeller's holdings the same way (total company control + reinvested dividends), his real wealth picture balloons dramatically. The comparison is messier than it appears: Irénée owned an operational manufacturing empire; Rockefeller owned equity stakes and was already being dismantled by 1913, forcing him to hold diversified securities rather than concentrated operational control.

Irénée's business model created a self-reinforcing monopoly through vertical integration and technological superiority—gunpowder dominance translated directly into chemicals, textiles, and materials manufacturing with minimal competition. He essentially invented industrial scale production for explosives, facing zero regulatory friction. Rockefeller, by contrast, built Standard Oil during the railroad boom when refining was commoditized and margins compressed constantly. He made his billions through ruthless consolidation (buying up 90% of refineries) rather than innovation, which is precisely why antitrust broke him up. Irénée's diversification saved him; Rockefeller's concentration ultimately exposed him.

The real kicker: Rockefeller was arguably wealthier on a purchasing-power basis if you count his post-breakup portfolio. Standard Oil's dissolution in 1911 actually made him richer—shareholders got pieces of every major oil company. By 1920, inflation-adjusted, he'd easily surpass $5B in total net worth. So the headline numbers obscure a deeper truth: Irénée built lasting industrial dominance, while Rockefeller built a wealth machine so powerful the government had to destroy it—and he got richer anyway. Both beat any modern billionaire on the relative-wealth-to-GDP metric.