> How were they supposed to predict things would change and agitate for something different without the hindsight you enjoy?

By comparing themselves to their counterparts in other countries. By 1955 there should have been alarm bells ringing as Europe re-industrialized. Same with 70s oil crisis but the best that US could do was to cripple Japan with Plaza Accords.

Americans even now have a mindset that nothing exists beyond their borders, one could assume it was worse back then.

> Exactly why do you think it is it unnatural?

Because only two industrialized countries were left standing after WW2 and those two countries enjoyed unnatural growth until others caught up - first the historical powers in Europe then Asia.