“We’re less shitty” just doesn’t have a ring to it.
The US had a massively growing economy for more than a century compared to other countries, and was pretty much war-free for the most part. A huge draw for people who were poor and had little hope in classist Europe. Yeah, the growing US engaged in a lot of fighting, but it wasn’t like Europe where a war with your neighboring country destroyed your food production and plunged the economy into chaos or something.