We have a game in a couple of days. Who do you idiots think would be running training or managing the team if we cleared out all the coaches right now with no interim in place? The point is to do less damage not more.
And even when an interim is appointed, keeping those coaches until the end of the season is fine if they can't secure their own staff. There's no rule that says the interim manager has to let them run things like Ole did. If they're told what to do, they'll do it, and their own ideas won't matter shit.
Even at Chelsea, half of Tuchel's coaching staff (Joe Edwards, Anthony Barry, Hilario and some of the fitness guys) were there under Lampard.
You don't need to make a clean sweep of the coaches to have a very different result.