Making movies is just like betting on horses at the racetrack.

O’Hara likens filmmaking to racetrack betting to stress how uncertain outcomes are in the movie business. Even with talent, preparation, and money behind a production, success depends on unpredictable factors—timing, audience taste, distribution, reviews, and sheer luck. The comparison also implies that insiders make educated guesses (as bettors study horses), but no amount of experience can eliminate risk. In this reading, the quote is both a pragmatic warning against overconfidence and a wry acknowledgment of why the industry can feel addictive: the possibility of a big payoff keeps people returning despite frequent losses.