That's only true if you compare game sales to movie box office revenues, and music sales (which have shrunk considerably since they peaked in the 1990s). Once you account for home video sales, streaming, theme park revenues, and merchandise sales, the movie industry dwarfs the gaming industry. Once you account for artist tour and merchandise sales, the music industry dwarfs the gaming industry.
That's only true if you compare game sales to movie box office revenues, and music sales (which have shrunk considerably since they peaked in the 1990s). Once you account for home video sales, streaming, theme park revenues, and merchandise sales, the movie industry dwarfs the gaming industry. Once you account for artist tour and merchandise sales, the music industry dwarfs the gaming industry.