"The US is rich for the same reason Rome, England, and Spain were"
Not really, have you been in England, Rome or Spain?
Rome legionaries were used to make roads and bridges and mining 90%of their time. If I show you the extensions of the land they "washed" to get mineral you won't believe it(you can see it using google earth, e.g in the north of spain, look for grooves around mountains).
England made itself rich because of commerce, like Spain(they took the risk to travel the ocean and won the first mover advantage, and when the rest of the world notice, it was late for them). That was what made them rich, not the military.
The US is rich because... IT IS RICH. It is a huge place with huge resources for a small population.
The US became the more powerful country on earth because Japan and Europe totally destroyed itself by the military in the WWII. The US waited for them to auto destroy, and then entered the world and finished it with all their cities untouched, 90% of the world gold reserves and creditor to them all, being able to force the dollar as world currency and english the official language of aviation, and naval commerce. Every body lost their colonies and US got them all(they just wanted the commerce and influence without having to build roads like English or Portuguese did in Africa).
Yes, it was a coincidence(being far away), no, US was not the most prosperous nation on Earth 200 years ago. If you believe in that, please study some real history. US was not the technical leader that is today thanks to all the Europeans that went there thanks to Hitler(militarization and economic totalitarism), the Edisons, the von Brauns and von Newmans.
Thomas Jefferson and other of the US founding fathers thought a permanent military and central banking would ruin the country because military people do nothing while things work at it should they need to create new enemies so they can justify their existence.
I had family members that were in Soviet Russia when something like 95% engineers were used in the war industry, while people needed cars, washing and sewer machines. This was not wealth for Russia, that was a bully inside. Mass media brainwashed them all them about how cool they were being able to destroy anybody else.(This strange pride remains today)
Today 60% of the engineering in US goes to war efforts, 50% of all their money to the military, so they can kill better, while the rest of the world expends significantly less.
They will talk about GPS, but the question is if this money expended in real economy would be able to create as much as the military does?