I know some will roll their eyes, however I feel obliged to say this now and again in such threads ...
Imagine if, by and large, all countries lived in (true) peace with each other. No need for all the nuclear (and other) weapons or military. Imagine those billions upon billions of £££/$$$ going towards positive things.
Yeah yeah I know it's fantasy land, however I just think it's such a shame humankind has never learned to live at peace.
Too much money to be made.