In abstract, if there were a way to rank employees by ROI and contribution perfectly fairly, I might not worry about layoffs personally. However:
1) In my career, I've never seen layoffs which were at all good at selecting the bottom 10%. Who gets dropped is pretty random.
2) I care about other people I work with. A 10% layoff means a few of my friends were hurt.
When I had a 10% paycut because the business needed it, it felt a little unfair, but I didn't leave. That same business raised my salary back up a year or two later. I'm still there, actually, and many people spend entire careers here.
I spend most of my hours working, and above some point, I care about having a humane employer, meaningful work, and a decent work environment much more than I do about salary.
Job stability also allows me to focus on my work over signalling. That works well if I value and enjoy my work (which I do).