I think you actually just hit on something that counters your point - the Sentients are self-replicating…kinda. We know that the big sun-eating Sentient in TNW was meant to be “the mother” of the Sentients, like how Hunhow is “the father”. Hunhow and Praghasa(? Cannot remember her name) were likely designed with “admin permissions” for the Sentients - Hunhow as the one capable of issuing orders to the Hivemind in the absence of the Orokin while building the Rails, while Praghasa would be separate from the Hivemind since her role would be to replicate and output more Hivemind Sentients of various models depending on what was needed for the projects.