Comment by nilkn

I'd think of it this way:

Folks who have institutional knowledge that is really critical to the company are likely treated quite well in prestigious roles and paid handsomely. If they take a modest buyout offer, it's probably because they were close to retirement anyway. Any truly critical role will have a succession plan. And if someone the company really doesn't want to lose signals they intend to take the offer without a credible succession plan, the company could just make them an even better personal offer to stay.

At the same time, I'm sure there are many folks who over-estimate how important their role and knowledge are to the company, especially to its future, which may look increasingly different from its past. Some of these people can become active blockers or political problems that are difficult, visible, and painful to deal with. Getting them to exit on their own is a win for the company, and it avoids the morale problem of visibly performance managing them or firing them.