Irregardless of right or wrong, does the Neocon (Leo Strauss) claim that empires must maintain their fiscal prosperity through endless warfare really hold water?
No, it doesn't.
Wherever you find in the world any nation that maintains a strong defense and national unity that also minds it's own business, you will find enormous prosperity and security. The longer a nation stays out of war, the more it prospers. This was true of the United States in 1916 before it was dragged into the first world war with the false flag called the Lusitania. Up until that time it had been isolated from the rest of the world's petty wars and had also been one of the most innovative and inventive nations on the planet and was rapidly becoming one of the most successful.
What about innovation? Doesn't warfare drive innovation?
The Swiss are some of the most innovative and inventive people on Earth despite the fact they have not been involved in a war since the 1500's.
It's really the introduction of fiat currency in 1912 under cover of darkness that inevitably leads to warfare. Fiat currency and endless conflicts travel hand-in-hand.
A healthy nation is based on a currency backed by metal, an intelligent educated citizenry and a national ethic of strong defense both for the military and civilian population. With these two ingredients there are no limits to what a country can achieve.
In contrast, all empires are living on borrowed time. They always experience parabolas of sharp ascent and decline with very ugly finales.
The Neocons got it wrong here just like every other idea they ever promoted. A good rule of thumb is that if it is an idea that originates with Neocons, I guarantee you it is abysmally stupid once you peel off the thin layer of credibility which is usually self-promoting, self-referential gibberish. Neoconservatives are the ultimate Luftmensch.