Keaton's $15M peak represents the highest salaries paid to any performer in 1920s cinema, yet he was essentially a salaried employee for studio moguls like Joseph Schenck. He negotiated massive annual contracts—the equivalent of $200M+ in peak earning years—but never owned his films, his likeness, or his distribution rights. Studios controlled everything downstream. Chaplin, by contrast, founded United Artists in 1919 specifically to own his work end-to-end. This single decision meant that every dollar of 'The Great Dictator's' $7.5M gross flowed directly to him rather than to a middleman. Keaton was paid like a superstar; Chaplin was structured like a mogul.

The predatory studio system of the 1920s-30s actively stripped Keaton of wealth through a combination of bad deals, studio takeovers, and a devastating contract with MGM that paid him a fixed salary while the studio pocketed all film revenues. His 1928 divorce was also financially catastrophic—California community property law plus alimony obligations drained what remained. Chaplin avoided these traps partly through sheer control freak temperament and partly through luck: he built his empire early enough to retain leverage. He also diversified into directing, producing, and composing—Chaplain scored his own films, adding another revenue stream Keaton never captured.

The real kicker is longevity as a wealth-building tool. Chaplin kept working, directing, and licensing his image into his late 80s, allowing compound growth of his catalog value. Keaton's career imploded by the 1930s (sound film didn't suit his genius), and he spent decades in semi-retirement with zero ongoing income from his back catalog. By the time classic film restoration and home video made silent films valuable again in the 1970s-80s, Chaplin's estate was positioned to capitalize; Keaton's rights were scattered or dormant. The $5M gap reflects not talent but timing, ownership structures, and the willingness to say no to bad studio deals.