The wealth gap fundamentally comes down to market addressability and margin structure. Rockefeller controlled 90% of oil refining—an oligopoly that generated massive absolute profits but served a relatively fixed industrial customer base. Eastman, by contrast, created an entirely new consumer category by making photography affordable to the masses. A Kodak camera cost $25 in 1888 (roughly $800 today), undercutting professional equipment by 90%. This wasn't just cheaper; it was psychologically different. Eastman captured billions of occasional users, not thousands of industrial buyers. His recurring revenue model—sell cheap cameras, profit on film sales—created a razor-and-blade machine that compound for decades. Rockefeller's monopoly was powerful but finite; Eastman's market expansion was infinite.

The structural difference matters enormously. Rockefeller's $340M peak was built on a single commodity controlled through consolidation—powerful, but vulnerable to antitrust and competition. His fortune was also taxed at 90%+ rates by the time he died, and Standard Oil's breakup diluted his holdings. Eastman, meanwhile, owned a consumer brand with genuine switching costs and network effects (everyone used Kodak because everyone used Kodak). His $1.45B empire had pricing power and customer stickiness that oil refining couldn't match. He also reinvested aggressively in R&D and marketing, while Rockefeller focused on efficiency and cost-cutting. Different philosophies, different valuations.

Most critically, Eastman's timing aligned with wealth accumulation curves. Photography was a 60-year growth story (1880-1940) with margins expanding as scale increased. Oil refining was already consolidating when Rockefeller took over—he inherited a fragmented market and unified it for profit extraction. By the time Eastman was building, consumer spending was accelerating faster than industrial spending. His bet on the American consumer in the early 1900s—when disposable income was rising—paid exponentially more than Rockefeller's bet on industrial efficiency. Eastman died richer because he rode a bigger wave.