Rockefeller's fortune was built on controlling a bottleneck—90% of oil refining in an era when oil was scarce and regulated through market manipulation. His $90 million annual revenue came from high margins on limited supply, but the absolute addressable market was constrained by both technology and geography. When the Sherman Antitrust Act fragmented Standard Oil in 1911, his wealth actually diversified into multiple still-valuable companies, but the core empire was artificially capped. He was a titan of scarcity economics.

Walton exploited the opposite dynamic: unlimited scale through logistics, supply chain domination, and relentless volume. Walmart's "Everyday Low Price" model meant razor-thin margins (often 2-3%) on astronomical turnover. By 1992, Walmart generated $50+ billion in annual revenue—over 500x Rockefeller's peak annual take—and Sam owned roughly 50% of the company. He captured value not through pricing power but through operational excellence and real estate accumulation. The retail sector's total addressable market was exponentially larger than oil refining.

The inflation math also tells the story: Rockefeller's wealth in 1913 was genuinely staggering for its era, but it compounds poorly. Walton's heirs benefited from a publicly traded equity stake that appreciated for 30 years post-death while benefiting from modern portfolio diversification. Rockefeller's heirs inherited fractured oil interests; Walton's heirs inherited a compounding machine. Modern oligopolies (retail, tech) generate more absolute wealth than industrial monopolies because they operate in larger, global markets with network effects.