Social Darwinism held that those made better or worse by industrialization were based on the natural predisposition of the people effected. For those who were made better off, the success of those people demonstrated that they had a well-evolved culture and this expansion would help remove or improve underperforming cultures, which were those "chosen" by the fact that they were performing poorly.
All in all, according to the Social Darwinist, Imperialism was the natural expansion and success of a well-evolved culture and this expansion would help remove or improve underperforming cultures.
social darwinism was used to justify imperialism because social darwinism was the idea that the stronger race would survive and the weaker would die off. in many cases imperialism was justified by the thought that the country being taken over was weaker and needed help, thus the "greater country" could force its customs on the other country.
I think what you're trying to ask is that the US expands to all of NA. That would be manifest destiny.
The wealthy elite in less developed countries typically do not provide a significant amount of personal savings for domestic capital formation if the question must be worded as "do not." However, wealthy elites in less developed countries often DO regard security as important in their investments and therefore invest in foreign companies and overseas where there is greater security and growth potential for their investments.
They are both Gods and they are both about the Gods story.