Assuming at-will employment, the employer can always eliminate jobs, BK or making profits hand-over-fist. No practical claim by ex-employees if their job is eliminated.

If an employee is fired, and their job is filled by someone else, then you'd need some reasonable basis, progressive discipline, PIP, etc

But (legit) layoffs don't require any justification at all, impersonal business decision.

When I did fortune 500 white collar, we *always* had a layoff list (in priority order) ready to go because the C-suite might give middle managers 24 hours to decide who to keep and who to cut. The jobs themselves would often get completely redefined to match up with the folks who kept their jobs, and the work that had to get done.

So the theory is that layoffs are done by job/position, the reality is that it still comes down to personalities in many cases. Sometimes they just shutter a whole division or something like that, then you know it's fair because everybody got canned.