"In Hollywood, people often need to create a reasonable sized business, have it work for a year or two, and then it falls apart. That's what a film is. Most people's engagement in this business is only a few months, maybe less, no matter how well they do. Therefore you need to get hired again, and again, and again.

In programming..."

In programming it's exactly the same. No one works in a software project for decades, and most gigs last 1-2 years until the programmer either moves to management or takes another project.