Trump tries to sabotage the next administration.
This is revenge against the professional civil service which he feels has tried to thwart him for the last four years. Biden can undo most of it with another executive order; a Democrat Congress can codify protections for the civil service into law to protect against future wannabe dictators.
He must think he's gonna win. This would enable Biden to drain the swamp himself. Let's hope so.
Not so much that. It's an anti-union and anti-civil service measure. "The swamp" is made of lobbyists and big donors who write bills and then present them through congressmen and senators, tailored to their special interests. The swamp is all about money. Weakening the professional civil service and driving expertise out will make the swamp even murkier.