US imperialism didn’t happen until the 1950s, well after the war.

this was, in part, due to the private investments from large American companies at the time. in-fact, the American economy was booming for three reasons

1. war was over and people were desperate to find stability and peace
2. Americans at home got through the war mostly unscathed and now had an abundance of work which in-turn made an abundance of money to spend
3. Europe desperately needed materials and products to rebuild their own economy, this only further boosted American GDP from a previously untouched market. private investment took place from American companies within Europe to increase profits further.

in a sense, because Europe was so weak after the war it only fed US corporate imperialism. Had Europe been able to stand on its own the United States might not have had such an industrial boon and similarities between Europe and the US might have not been so significant.

one might even draw the strong correlation between American corporate interests and total subservience of government alliances at that time. our government had, up until then, mostly stayed neutral to concerns between corporations and citizens. this changed though because of the newly created military industrial complex that was created to feed the war. afterwards you had defense contractors that saw dollar signs, and the tradition still goes to this day.

speculation on my part, the political climate of the current day is the fruit bore from that union of corporate and state all those years ago and this has been the agenda of the American elite all along and they are currently in the final seconds of the “game of thrones”.