The standard of living in the world today and certainly in the US would be lower. WWII, for all the death and destruction it brought, also ushered in a long bought of peace and forced structure and civility among many nations.
You and I may or may not exist today and this continent may have been conquered by tyrannical Superpowers. Check the rise and fall of the Roman Empire. Once the feeding and conquering of nations and people proves successful for the wealth and sustainability of a Dictatorship, it needs to continue to feed.
I say it is a huge deal and the world, including America, would not be as great of a place. Call me patriotic, but I enjoy with confidence our status as the greatest nation on earth, even with our current and past flaws.
I get it. Empire agrees with you. That's fine. It's an honest position. And I understand you value our actual history too much to bear consideration of alternate histories. That's fine too. Romanticism is not necessarily a bad thing in a person.