I suspect some of the always use new spokes harks back to the '70s-80s when a box of 100 chrome plate or stainless spokes could be had for $10-12
and if you went with unplated straight gauge perhaps $7 or so per hundred (remember Union spokes from Connecticut?). Now spokes are sold per
wheel at 10-15x the costs of yesteryear. Of course a full Campy bike then was $250-500 depending on which Italian frame maker was selected so
maybe the cost is proportionate.... (which I doubt).