Another factor is some cars (like mine) were repaired by collision shops in the 70's when these cars had nothing beyond daily driver value and zero aftermarket parts availability. Getting the car on the back road quickly was the first priority with low cost being the second.
One of the old timers I know told me how a place he worked would bang out the dents with a slide hammer, big mallets and other rough house tools then lather on the bondo like frosting a cake. When it was dry they would file and sand their creation until it looked close enough. The car would be sent to him to spray and ship out the door. If they did replace a panel, lap seams and mud were the name of the game. At several places he worked in that era it was all about speed and the bosses would fire guys who weren't fast enough.
Either way it still boils down to quality taking a distant second place to quantity.
Thankfully shops like yours and several others actually care about the cars they build and the customers they serve. Thank you for that and thank you for sharing some really nice work.