Earlier quoted context omitted.
The basic perversity is building a gigantic military in peacetime because the arms companies have enormous lobbying power. Everything else flows from and is secondary to that.
Isn't it more complicated than that? Today being behind on military technology by as little as 5 years can be decisive in confrontation. The last decade has brought huge changes in military technology including super and hypersonic missile delivery systems (these can defeat the US's current interception capabilities), THAAD technology, directed energy weapons, new reactive armors, satellite bombing systems, startling…
I'm sceptical that the military might does that much to make the US rich besides providing basic peace. Obviously things would be screwed if WW3 started.
The US has got rich mostly by trade and enterprise and producing much of the worlds high value stuff. Spending a huge portion of governments revenues on the military rather than things like education, R&D and science has probably been a drag on growth.