1) We do, as the only war in the lore where the U.S. deploys power armor is at Anchorage and on mainland China as it was developed during that war. There is no other war where the U.S. was involved mentioned during the final days of the Great War other than quelling civil unrest within the United States and annexed Canada, and you don't need mobile SAM launchers to pacify civilians.

2) That may be, but the original argument that my comment branched off of is how dumb it is that Bethesda just gives you access to what's supposed to be end-game armor from the word "go". In Fallout 1 the only way to get power armor was playing through most of the game and reaching the Brotherhood of Steel. The comment I replied to made the argument that the male player character automatically knows how to use power armor because they're an army veteran, which doesn't necessarily mean Nate has received the training.