That’s the problem, he didn’t for some insane reason. If you are a member of another party’s administration, after he got elected, his first act should have been writing 30,000 or more pink slips thanking them, and warning that any material of property damage, they will be prosecuted.
I imagine Trump was “advised” NOT to fire them, by one of the many lying back stabbers who pretended they were on his side. And Trump, being a nice guy, and a Washington neophyte, thought he could trust his advisors. On 1/21/20, I hope he cleans house wholesale, and throws out every stinking Obama/Clinton leftover.