Not worried, because Dr Carson wants to stay on as adviser to POTUS Trump & his Admin.
As Minutegal has presciently posted, not all of these Medicare age people want to face the daily grind of life in DC or try to manage humongous bureaucracies which in itself is a onerous task to execute on day to day basis. People like Rudy, Sessions, Carson are close to septuagenarians. IMHO they are much more effective in guiding general policy directions.
Transition team says president-elect met with Henry Kissinger, Trump: "appreciate him sharing his thoughts with me"