Experience in the political arena is a worthless pile of shit to me, and I've been saying that for decades. I want term limits, I want new blood, I think experience is what lurks at the very bottom of the swamp. I think the more experience uou have in the political arena, the more worthless you are (general rule, with exceptions, no pun intended)
Experience in the military arena is another story, and I'm pretty sure there's tons of that still available to POTUS. Mattis was holding a political position Many, if not most people who held this position have had NO MILITARY background. I think Mattis may be the first former general to hold that position. I remember libtard nation complaining about Trump appointing a war monger to the position, and how he was unqualified because Obama had fired him. Now they love him of course, because they have no foundation, they're literally dust in the wind.
I understand you think a military man is right for the position, and I like Mattis too. I'm pointing out the inconsistencies and lying hypocrisy of libtard nation, they have no soul. I'm pointing out that it's OK for cabinet members to leave, it's not some catastrophic event until proven otherwise which I trust won't happen. And I'm pointing out that it's unusual, not the norm, for a military man to hold that position to begin with.