You are right. SD is a sideshow to many major companies, not home. That being said, the major employers that are here are often Military. We are currently fighting multiple wars and military spending is through the roof right now, and alot of boats are being kept afloat due to our war spending.
A buddy of mine works for a military contractor, makes damn good money too. Able to keep his head above water only becasue of his “government job premium” and a boatload of overtime. If the war spending ever ends, the SD economy will do a whole lot worse IMO.