I've heard that the computer visual effects field, particularly for the film industry, is heavily saturated with labour. Too many CGI artists, not enough jobs.

This is what happens when labour supply outstrips demand - the competition for those few jobs is so high that people have to be willing to accept shit wages and shit working conditions because if you demand better, there's a thousand people lined up who will do your job for less than you're demanding. That's how excess labour supply lowers the value of labour. And it doesn't stop at that industry. It ripples across the entire job market because those are jobless people who have to go out and find jobs elsewhere, which means adding supply to other industries' labour supply thus devaluating that labour too.

This of course benefits the people at the top because they get to pay rock bottom wages and benefits from their labour and treat their employees like slaves.