You might like to read about the Writers Guild in Hollywood. Highly organized, high salaries far surpassing even that of tech, with graduates in the top percentiles coming into 500k/yr salaries fresh out of graduation, all union.
None of that applies to software development which is a global phenomena.
Many jobs are more difficult than hacking on Angular bs all day, it’s not like most devs implicitly deserve the high pay they enjoy here in the States.
Not to mention, most people are far more likely to pay for a movie than for a piece of software, excluding video games.
Hollywood filmmaking is indeed not a universal phenoma. There are other centers of filmmaking outside the US that aren't part of this guild.