That's true, the rediscovery of American heritage clothing may have happened anyway, but I have to imagine the boom in American workwear/sportswear has been mad

That's true, the rediscovery of American heritage clothing may have happened anyway, but I have to imagine the boom in American workwear/sportswear has been made dramatically easier for modern designers thanks to the Japanese otaku that have studiously collected, documented it (Free & Easy, Lightning Magazines) and continued to produce it (Buzz Ricksons, Real McCoy). Due to this, a route to revitalizing an American heritage brand is to simply hire a great Japanese designer. If no one had cared I do think it would have been a much more difficult process and I do think it would have been likely that some knowledge could have been lost.