Industry towns emerge due to the critical mass of having employees, entrepreneurs, suppliers, business partners, potential customers, and investors in the same geographic location. It’s San Francisco for tech, Hollywood for the movie industry, NYC for finance.
If you want to go into the movie business and someone told you to go to San Francisco instead of Hollywood, you would think they are nuts. It does not mean that you could not have a movie career in San Francisco - but it would be more challenging. Movies are written by authors who could live anywhere, are filmed onsite around the world, and could be digitally edited from anywhere. Actors could fly to any site in the world to act. But for the Western markets most of the critical mass of the industry still happens in Hollywood.