Being the imperial power has vast benefits, do you think Rome ruled its provinces just so they had a way to spend money? Being the global power is literally worth money. It's hard to say how much, but I'm pretty sure it's larger than your military expenses.
That said, I'd love to see the US cut back, because your benefit comes at somebody else's cost.
If the net benefit to the US is positive however, do you believe the majority of people would be happy to work more to have the same standard of living, or the majority of well-off Americans would be happy to pay European level taxes to redistribute wealth within the US? I have sincere doubts on both fronts.
All the money made being an imperial power just lines the pockets of the rich.