I am actually most sympathetic to the idea that the military is the single really identifiable point where large-scale waste is identifiable. However, even that spending is dwarfed by health and welfare transfer payments, and procurement is a fraction of military spending. So... yeah, procurement is big and wasteful. But in 2013 (the last year that Wikipedia had) we've got around ~100B of procurement out of 610B of military spending and out of 3.45 trillion dollars of spending.
That's like 1 dollar out of 34, probably not all 100% wasted either.
I'm not going to argue that there's not a lot of wasteful government spending - transfer payments that don't need to happen, waste in healthcare, etc. I just don't see much of a path towards a really substantial change in tax rates that would emerge from 'cutting waste'. Tackling transfer payments IMO is a much bigger deal, but this is also likely unfixable for political reasons (essentially the middle class have to be bribed to support anti-poverty programs by including them in the transfer payment merry-go-round).