Actually, the plan to provide 8 months of additional service is largely directed at those nearing retirement, or beyond it, and they get one more year in their formula for retirement. This purges some of the highest compensated folks, opens a position, or should I say empties it.
But even this approach was done in a hostile way, and not a friendly way. If you want to get someone to do something, you do not insult them, kick them in the teeth, or outright threaten them, for that can work contrary to the desired goal.
These memos are utterly stupid. Musk really is out of his element dealing with government, and he and Trump will have a falling out soon, if Trump is smart.