Long time ago they modded the Turkeys. Supposedly protein production was optimized but the turkeys were seven foot, cut like Olympian emus.
People were afraid of them. A whole earth catalog reading agriculturalist might go out to feed the turkeys and never return.
NPCs were similarly optimized (from the pedo cultist POV) by behavioral conditioning for credulousness, for social compliance and deference to authority.
These qualities are valuable in a slave population, as the history of servile rebellions teaches. The cult media conditioning begins in infancy and if uninterrupted continues until death.
The Spartans, whom NPCs admire for their military prowess, kept a huge NPC population to do everything but fight. These ruthless pederasts required every Equal as the part of their initition to murder a helot at random.
This was done for the same reason pimps beat whores, to keep the helots down, terrified and attentive to their menial duties.
No different now with cubicle stuffers currently filling every square nano meter of our device screen with clamorous marketing kludge to destroy the attention span and render reflection unlikely.
For this reason, it is easier to create NPCs than to wake them up.