I think it is much deeper now than then, because we didn't 'know' about global warming then and had not yet reached peak oil. America still saw it was an effective deterrent to the Soviets nukes — the perceived leading threat of the time. And, the country still had a manufacturing base and jobs for the middle class.

Japan is a much smaller country than China and has a declining birth rate. Plus China is not only a competitor economically, but also a direct rival in terms of power, both soft and hard.

You're absolutely right that the U.S. has in living memory been through this sort of dark pessimism before, the difference now is, I think, that this time a majority of Americans suspect the old cure-alls that Reagan and the other snake oil peddlers come around selling won't work. And, while though many will buy what they have for sale - 9/11, 9/11, 9/11 - it is out of habit rather than hope.