Funny enough, I happened to notice just the other day that my old ULA pack, which I absolutely love and have used for 10 years, has a tiny "Made In Canada" on it. Even Cottage industries aren't fully localizable anymore. And what about the country of manufacture of the materials, especially the fabric which can be argued contains most of the technological (as well as the actual) substance. These will usually not be manufactured in the US, though they might have been invented and marketed here.
This is not to mentioned the ex "Saudi Arabian" dinosaurs who came up with the raw materials. They should at least get a tag, or something ;)
Leaving aside the question of whether the "political" principle is even valid, from the practical point of view it may, for most products with any technical components, be moot. Cottage industries are *more*, not less susceptible to the need to purchase their materials and manufacturing from elsewhere once they start producing more than a few items per month. If you bought all the materials to hand make your own pack, would that be truly "made in America". I think not.