There's an excellent article in today's LA Times Calendar section about how Joss Whedon managed to buck trends and film the movie Serenity in Los Angeles -- thereby making many local movie craftspeople grateful.
The movie industry originally came to LA about 100 years ago because shooting here was cheaper -- the plentiful sunshine enabled longer shooting days. Today, outsiders may be surprised at how the entertainment industry dominates the town. It takes a lot of people to make a movie. The average person knows the names of some actors and a director or two. Some more discerning moviegoers may know the names of some writers and cinematographers, and perhaps some composers of movie scores. Yet many more names swell the credits of movies. There are probably few LA dwellers who don't know at least someone involved in movie or film production. The issue of movie and TV production moving to Canada and other countries is therefore a very real one for the working people of LA's entertainment industry, and all the other local businesses that they patronize.
Whedon isn't a purist; he states he will be shooting Wonder Woman in Australia. But his simple wish to make Serenity here because it's best for his wife and kids set an excellent example for Tinseltown movie creators.