The argument that you need “political experts” with decades of experience to navigate the “intricacies of politics” always cracked me up.
Rather they would talk about efficiency of the system. People who have more knowledge allow the system to move with greater inertia than if you were constantly changing out all the folks.
There is an optimization problem here, throw away everyone all the time and your lack of institutional knowledge will cause work to be redone more often than desired. Cycle none of those in power, and there is a lack of incentive to evolve along with other systems as they change.