Carnegie built his fortune the old-fashioned way: vertical integration and ruthless market consolidation. By 1901, he controlled 30% of all American steel production—a duopoly-adjacent position that took decades to construct and depended on massive capital expenditures in mills, equipment, and infrastructure. His wealth compounded through ownership stakes and reinvestment, but steel was a capital-intensive, slow-growth business with thin margins despite scale. Gillette, by contrast, discovered the recurring revenue model 70 years before SaaS became a verb. His safety razor solved genuine friction (straight razors were dangerous and required stropping), and the genius was the razor-and-blade model: give away the handle cheap, make your fortune on replaceable blades that customers repurchased weekly. This generated exponential cash flow with minimal marginal cost, which is why his peak purchasing power ($700M in 1915) dwarfed Carnegie's.

The structural advantage Gillette enjoyed was pure network effects plus habit formation. Once a man switched to safety razors, he was locked in for life—not by contract, but by convenience and cost. Carnegie's steel had to be sold deal-by-deal to railroads, construction firms, and manufacturers; Gillette's blades sold themselves through drugstores to millions of individual consumers. Scale in Gillette's model meant factories running hotter and faster, not massive new infrastructure investments. Carnegie built an empire; Gillette built a machine that printed money.

When Carnegie exited (selling to J.P. Morgan for $480M in 1901), he'd already peaked and was diversifying into philanthropy—a sign he'd wrung most juice from steel. Gillette, meanwhile, was hitting his stride in 1915, peak wealth years, suggesting his business model had room to run. This timing matters: Gillette's empire was younger, more scalable, and less dependent on industrial labor relations (Carnegie faced constant strikes and wage pressures). The $33M nominal gap masks a deeper truth—Gillette's business was worth exponentially more because it generated money faster with less friction.