>Or really old school, and consider the ancient Spartan social
>system as a pre-industrial military-industrial complex. :)

Which is explored to one degree or another in both Starship Troopers and the Draka, and both have interesting answers to Sparta's biggest problem (arguments about morality, beliefs systems aside for a second) as a society - sustaining the demographics of their military and governing elite...

Heinlein and Stirling posit some ways around the incredible shrinking Spartiate class problem...

Your helots may vary :)