Err yea, I know about the wars, my assistant principal was KIA during the surge (he was a NG reservist). The NG and Reserve troops actually going through the same basic and advanced training (depending on MOS) as active duty soldiers (albeit not as many trainings as they do after they get their stripes). On deployments the paygrade is also the same as active duty, they dont differ from paygrade. During the Iraq invasion, supporting all those active duty components required FOBs to be built continuously and maintained (building defenses, having soldiers occupy them, etc..) to maintain a presence around the country, along with a bunch of specialized logistical MOS's. So you had over 140,000-150,000 troops in just Iraq at that time, along with ongoing operations in Afghanistan, WHILE maintaining numerous bases around the globe (which require active duty presence, or at that instance, reservists would be placed in their stead, in hotspots like Korea, Japan, Germany, Bosnia, Kuwait, etc..)
Main point is: in today's modern age, even to invade and occupy a country like Iraq requires hundreds of thousands of troops, if the invasion wasnt a 'coalition', then the US would have had to double its numbers, again just for a country like Iraq. So think of an Iran or North Korea, that would definitely require way more, and thats how they are justifying the 600,000 active duty or so and wanting to expand that.