Yes, it has moved out of AoE3 - but could it perhaps be moved rather than closed? It seems like some interesting concepts have been brought up.
Also, the CIA numbers are quite believable and probably very accurate estimates. As for aid to those "rich" countries, the US does not give much aid as a nation to India. And less to China. Also, those countries aren't exactly rich. They wield significant (and very rapidly increasing) economic power, and both actually have quite powerful militaries, but the numbers used in that ranking were the GDP (maybe GNP...similary purposes for the numbers in either case) - not per capita. The problem is that both those countries have well over a billion people (just look at China - 1.3 billion - that .3 is larger than the entire US population). Those two countries combined have a third of the worlds population. And they have equally massive troubles, in large part resulting from overpopulation and foreign threat...hence giant expenditure. Also, foreign aid is used to establish allies and friends...and thus aid almost never goes to where it is needed most, but for politcal and international relations reasons.
As for Mercantilism, it may have peaked around the industrial revolution, as it helped the mother country sell its good, especially to its own colonies. But earler, i think the demands of mercantilism drove the industrial revolution, just as industrial advances made such an economic system possible. And either way, Spain started dropping from power around the early 1600s and was finished as a global power 1700s as they could not meet the demands of their own colonies (actually the decline of Spain is far more complicated, but thats thereason within these contexts). Even in the early 1800's Spain still owned all of the Americas (South America, Central America, Carribean, Mexico - including everything West of the Mississippi, Florida, , with the exception of Brazil (Portugal), Louisiana (French - and everything between mississippi and appalachian), the 13 British colonies, and Canada (British). The problem was that Spain could not manage its colonies well, and failed to develop diverse economic strucutres in their colonies (Britain succeeded at it exceptionally well), which is why, in part, Latin American countries still have trouble with their economies, at least in comparison to the United States. That, admittedly, has been ridiculously oversimplified, but it captures the general relationships.
And Mercantalism has definately been obsolete for a very long time now (the modern economic numbers weren't referring to mercantilism, it was a seperate discussion)...our economic structure right now is really really odd , actually. It essentially only has value because we believe it does.
I agree that thats why muskets obsoleted long bows. But this was simply an extension of the way crossbows were obsoleting long bows. Yes, long bows were better, but a simple peasant could be taught how to operate either a cross bow or a musket in less than a day of training, and then kill a knight or longbowman that had been training his entire life. The reason muskets then replaced crossbows is cost and power. Crossbows were more accurate and had more range (early muskets had more range on a good day, but that was unreliable - later muskets, of course, had much better capabilities), but required that the user be physically strong. The ultimate reason (besides cost), is that even crossbow bolts had to fired in a balistic tragectory to a greater degree than musket balls had to be fired (and crossbows aren't as good as longbows or musket balls in ballistic trajectory...they are less likely to hit with the point down). Thus, a crossbow was easily better in a one on one fight, but was less practical for massed fire.