IIRC Jay, such standards are NEMA standards....
And since the industry is using the same - or nearly the same --wire drawing machines it's not an issue of economics to have the product information rolled onto the outer cover.
This is also how the NEMA crowd brands their wire.
As you might imagine, not one of the NEMA players wants knock-off THHN entering the American market.
At some point, legal jargon has to stop and common sense an common practice have to 'step up.'