I couldn't finish the article. Equal parts potentially valid and crap. The Japanese and Americans are more alike than different as consumers and that includes music. We have far more of it native to our country and while traditional jazz may be marginalized, it helped lay the foundations for blues, R&B, rock/rockabilly, and more. The latter further mingled with folk/bluegrass to get to "country", although country swing bands were most certainly jazz influenced. R&B has debateably become hip hop, rock evolved in many forms, and as covered by others, jazz certainly didn't stand still. While it is not likely to ever regain its former prominence, it is one of the foundation musics of America and it along with it's many descendants has been HUGELY influential to the music of the world.
Overall, however, he misses the fact that we are ever evolving population, human beings that is. While we should embrace and know our history at a far higher level, were are generally forward focused. That said, if someone can bring it back to the fore, some young/hip/appealing new artist that hits the teen through 30s demographic just right, there could be a big resurgence. I doubt it, but you never know.