[Jtsummers]

"unfair" is, in my view, the wrong way to frame it. It's a question of cost/benefit analysis. Does the US, by virtue of its effective global military presence, gain more through spending and maintaining it, in order to protect allies and its own interests, even if said allies fail to contribute a "fair" amount? (Whatever that may mean)

A loss of military hegemony will most likely reduce the US's global political and economic role as other countries move to fill that void or take advantage of the absence (China, Russia, at present). The net effect will likely be a shrinking of the US economy in the end, and not growth or even sustainment.