Also- pretty certain (memory might be wrong if it's a prequel memory) but Leto knew about this who plot openly with Ix- Ix wasn't hiding the fact they were trying to develop these artificial navigators. If he was speaking English instead of Gallach, I am sure the words out of his mouth would of been a 'Meh' upon hearing of it. He wasn't going to spearhead this one encouragement wise, or even recommending the idea- but wasn't keen on discouraging it either, knowing damn well it would catch on in the end- but a end well beyond his end and personal concern.
"Leto felt that it might even be possible that the Ixians had achieved a partial success with their machine to amplify the linear prescience of a Guild Navigator. A small blip
in the flow of great events might have escaped him. Could they really make such a machine? What a marvel that would be! Purposefully, he refused to use his powers for even the smallest search through this possibility."
GEoD, p. 162
""You were born within this machine your masters are trying to perfect for the Guild," Leto said."
GEoD p. 164 (to Hwi after he did a temporal probe of her history
I'd thought there was another quote where Leto rails at the Ixian ambassador saying that the machine will never work and that the Ixians are cheating the Guild out of spice, but that was Siona's interpretation of Leto's message to the ambassador... And Siona is kind of a horrible person.
Leto definitely knew that the Ixians were working on a machine navigator but he doubted it would ever work, at least until he met with Hwi and basically figured out that no-globe-ness was a side effect of the navigation machine. He also finds a Guild Navigator working with the Ixians and is bemused that they thought a Navigator could hide them from the God Emperor.
So... the Ixians never set out to build a no-room; they were building a navigation machine and discovered that Guild Navigators couldn't see inside it... so they made a baby in it. Which is what I would do I guess.
Question: In the prologue for GEoD the archaeologist speculates that the room that they found the journals in might be the first no-room, but it seems to me that it would predate the Ixian machine by quite awhile and would have been built without their help, right? Did Leto already know how to build simple no-rooms?
Also, my thoughts about the necessity of the sandworm cycle restarting (and Leto is clearly convinced that this is necessary for the Golden Path to hold true) was based on the theory that mankind needed the spice to fuel the Scattering. But if the Scattering was instead fueled by Ixian navigation computers... why does the sandworm cycle need to be restarted to ensure the Golden Path? Is it possible that Leto was wrong about needing the sandworms to come back? He admits that even he is fallible at some point and his refusal to look for his own death or to see if the navigation machine was ever completed may have blinded him.
Is it possible that he knew the Golden Path held true but not entirely why
it did? Did he ensure the Golden Path not because he went back into the sand, but merely through his tyranny- pressing the Ixians and Guild to find a substitute for Navigators that could lead to the Scattering.
His sacrifice is still needed; mankind still has to be kept bottled up and taught the lesson of Leto's Peace, but maybe the return of the sandworms is not a necessary component for the Golden Path once the navigation computer has been invented.