The US is pretty much an empire, in the sense that they had a dramatic territorial expansion in the first 100 years of its existence. It started out as 13 colonies and quickly engulfed everything up to the pacific coast. That's also conquest.
And yeah, colonialism and modern imperialism played an important role in the development of the industrial revolution. Cheap resources extracted from the colonies were transformed into goods en masse back home, only to sell them again to their colonies. Most of the historical buildings in Amsterdam for example, were financed with colonial money.
Protestant work ethic is an enormous factor