Never in any layoff I've been a part of, have the least talented workers been let go first. It's usually by category: contractors, age (early-retirement), department, or job description.

I highly doubt that's true. It may be what you want in an ideal world, but in reality, very few, if any, companies of this size have any internal ranking system that can accurately identify the 1000 least talented people company-wide. More likely, they're laying off the last 1000 hired if they want to optimize for losing the least institutional knowledge, the first 1000 hired if they want to optimize for immediate labor cost savings, or just laying off all the people that are part of teams working on projects that got scrapped, who happened to be in the wrong place at the wrong time.

In larger companies, for some values of “talented” that comprises non-technical factors like political acumen, yes. If the “talented” label is meant as a shorthand for some kind of meritocratic scale, then I have my doubts about that.

I’ve long since lost my astonishment at the revealed preferences in layoff selection criteria. It isn’t a complete Machiavellian free-for-all, but merit and fine-grained logic usually don’t prevail at the top of the criteria list in the trenches.

If your statement is true, then the inverse must also hold: hiring is based on merit, which we all know to be untrue.

I've heard people claim this, but I've never actually seen it happen in practice.