It could be that they don't want him in a position of power to stop or change something that is going to happen before the 20th. The deep state figures that they have certain people in place that will thwart Trump's plans. He tends to wait until he needs to move before firing so that they have less time to come up with a work around. Like the Sec Def recently or that guy in charge of the computers at NCSWIC's just after the election.
It could be that they don't want him in a position of power to stop or change something that is going to happen before the 20th. The deep state figures that they have certain people in place that will thwart Trump's plans. He tends to wait until he needs to move before firing so that they have less time to come up with a work around. Like the Sec Def recently or that guy in charge of the computers at NCSWIC's just after the election.