It took me fifteen years to discover I had no talent for writing, but I couldn't give it up because by that time I was too famous.

Benchley’s joke turns the usual narrative of artistic vocation upside down. Instead of talent producing fame, fame becomes the trap that prevents honest self-assessment and change. The line satirizes both the insecurity of writers—who often suspect they’re impostors—and the public’s tendency to equate notoriety with merit. It also pokes fun at the professionalization of authorship: once a persona and audience are established, the writer may feel compelled to keep producing regardless of private doubts. The humor depends on the exaggerated time span (“fifteen years”) and the deadpan logic that celebrity, not ability, dictates persistence.