Sure. But failure to fire the people being insubordinate is also a failure of the President's leadership.

The people being insubordinate may well not be political appointees that serve at the pleasure of the President and who therefore could be fired by the President (and, procedurally, the President can't directly institute the processes which would lead to firing them, either), and while the President can fire the political appointees above them, the President can't replace those political appointees without the cooperation of the Senate (unless the opportunity for a recess appointment pops up.)

Failure to fire those political appointees for not firing insubordinates is hardly defensible.

Wenn das der Führer wüsste..