Let's say you run a company and you want to reduce staff. Let's also say you want to make an unpopular decision (or multiple unpopular decisions) that you know will drive a certain percentage of your staff to leave the company. Wouldn't it make the most sense to announce those decisions before making layoffs? Let people self select whether they want to stay and work for you and then make your layoffs after to ensure…
He's got huge debt and declining revenue - both of his own making - so he doesn't have time for employees to self-select based on minor incentives. He has to strip down the car fast while somehow also keeping it road-worthy and operational. He also wants to recreate the place per his own vision, so it makes sense to get rid of as many people carrying the previous culture as you can and then start hiring as necessary with the kind of people you want.