Budget "waste" is a cool concept, because it is both truth and nonsense at the same time.
The US Capitol building is an expensive and beautiful edifice representing US power and prestige. However, all Congress really needs is two lecture halls of appropriate size, as seen in college campuses, and a few office buildings to house their staff and a few hearing rooms. Few people would consider the Capitol a waste, but in terms of bare bones requirements, it certainly is. It's need is ephemeral.
Public parks, high speed roadways, rail, public library's... all of these things are not absolutely essential, and can be termed waste. Except they provide for the public welfare in various ways, to various degrees.
Waste is defined as things one pays for but does not use.
The truth is, there is nobody who sits around figuring out how to bonfire as much taxpayer money as possible.
Every project makes sense to someone, in terms of defense, or beneficial infrastructure, or economic development, public enjoyment, or employment, or a show project to help with re-election.
Very little of the waste comes from individual projects. Most of it comes from massive profiteering from the private contractors that build those projects. I do happen to think our military is oversized and geared to fight a type of war that doesn't exist anymore- forget about the power source of our submarines- what the heck do we need them for in the first place? It's an outmoded form of combat, because the few operators who would be in a position to take a serious arguing posture with a US Navy warship can detect our submarines easily.
But on the other hand, having such weapons available if China or Russia can get serious about underwater boats... so is it waste?