Even then, I mean it's not like they take the entire list of artists, producers, engineers, DDs, QA, sort by salary, and then say "who can we pick from the top half of this list?"
It's always strategic, it's just on a different scale. If they have too many DDs and not enough things for them to direct, they probably let go of the DDs who have the lowest impact. If their planning indicates they need X amount of engineering capacity to complete the project on time and they have Y, and Y > X, then they're not going to look at non-engineers for layoffs, and even STILL salary is going to be the last thing they look at, even among engineers. They're just going to sit into a room with the numbers like current project capacity, required global capacity, required capacity per project, and a list of engineers, and they're going to shuffle them around between projects seeing might have the skills to fit into which group and trying different combinations until required capacity and actual capacity match up.
Then they're going to look at all the combinations that work, see who is left out of each one, and fire the people who have the lowest performance, or maybe even that people just don't like the most.
It's never as simple as "senior guys are the most safe" or "junior guys are the most safe". The only people who are definitely safe are the 2-3 most senior engineers on the project.