It may be that Turchin’s a little too embedded in the modern world, where combat is dominated by Lanchester’s Square Law and skilled concentration is the key to tactical victory. The ancient battlefield was somewhat more linear: if both sides were playing smart it was difficult to bring multiple men to bear against any single enemy. This is in large part why pre-modern battles tended to involve remarkably few casualties until one side broke. The ways around this, generally based on polearms like pikes that allow multiple men to attack a single foe, are invalidated by the “stickiness” of the Holtzmann field; a long spear becomes very easy to parry with your sword if its mobility is hindered by a kinetic-energy-sapping shield. Individual combat in Dune is all about getting in close and personal with finesse-weapons.

This pattern still presents in modern warfare, because it’s the result of certain human psychological characteristics, but to nothing like the same extent. The best modern armies often take at least as many casualties in tactical victory as in tactical defeat, whereas exceptional ancient armies could go from victory to victory suffering only single-digit casualty percentages. Note that I’m referring only to tactically “fair” fights, none of this M1-Abrams vs. Toyota Hilux we’ve been dealing with lately.

In Dune, this effect combines with the Spacing Guild injunction against space-combat, the religious injunction against computers (and thus computer targeting systems that would make precision orbital bombardment possible), and the pragmatic injunction against atomic bombardment to render a galactic empire that can be ruled (and conquered) with no more than a few million soldiers.

Turchin also ignores that the Sardaukar are as brutally disciplined as they are brutally skilled. The Fremen were nothing until Paul brought them the same discipline under the flag of religious fanaticism.