Are all of these NOS tube inventories real? How have we not consumed them already?

Oh yes we have consumed it long ago, what remains as NOS even NIB (different thing) is any surplus from the 80’s for military use and most likely for the non popular ones. Otherwise term NOS is catchy and a good trap. That does not mean that a used tube is no good but is silly to pay as NOS. Still some collections will surely have gems and hunting them down is fun.
G