A rational company would not buy out an employee that they're going to be rehiring.

You cannot act with perfect information when you're making an offer to 25% of a company that size. If they were able to and willing to plan this on a per-person basis, they wouldn't be in the position of mass-buyouts.

It's very common in these situations to target every org in the company with a goal of X% reduction. If a small fraction of these teams now need extra headcount, easy enough to allow those teams to hire. Usually you don't keep the severance if you return in under X days.

I've personally been laid off, only for the post-re-org team to hire several people, including asking to rehire me. It's rare, and those affected should probably plan to find new jobs, but it happens.

Yes, but companies realise the important cogs much later in the process.

typically in that case the boomerang is they come back but as a consultant. just doing the same thing they were doing before but at a different rate. usually higher to cover health ins plus a bit of a bonus.

But with the job market the way it is, they could re-hire at a lower compensation?