If we weren't the economic power at the end of WW2 and for some time late, who was? And if you don't equate postwar economic strength to our home grown manufacturing ability then what would you attribute it to? Do you suppose there aren't other charts that relate our manufacturing to the strength of manufacturing in "underdeveloped" countries ... countries with significantly less expensive workforces?
For instance, as the cost of living has increased in Japan, have you noted that far fewer of our imported goods come from Japan? I've noted that Japanese audio equipment we get here isn't made in Japan, but look at the Japanese sites and you find the bottom tier stuff there is made in China and the top tier stuff is made in Japan ... often the same with photographic equipment. We apparently surrendered both markets years ago - not because of inability, resources, or tariffs, but because we couldn't match foreign labor rates. The same is happening to the Japanese, and likewise hurting their economy. By the way, the Japanese play and have played the "tariff" game a little differently ... their radio and TV bands differ from ours, their power is 60 Hz in some places and 50 in others, and they drive on the wrong side of the road - those are all barriers to entry just as much as a steep tariff.