Why arenít computers used to combat mind worms? I mean even today we have automatic turrets capable of taking down cruise missiles and flying drones with air-to-ground weaponry. What's the problem with modifying it a little bit for countering mind worms? Even simpler - just put some napalm emitters on your diamond hover tank - voila, worms would be fried. Or, if automation is prohibited for some reason, make your turrets remote-controlled with operators safely at base.
The GURPS book mentions that mind worm boils interfere with technology, which prevents even late-game AIs from functioning properly in their vicinity. That does raise another question though: How is the cybernetic consciousness able to withstand the worms at all?
Well, why would computers be immune to psychic powers? Sure, it's generally accepted that machines, no matter how intelligent they are, don't have souls, ghosts or magic, but as long as the mechanism behind the mind powers is left unexplained, there's no real reason for this. Perhaps psychic powers in Alpha Centauri affect all minds equally, independently of whether they're made of meat. And a simpler mind, like the crude target-seeking algorithm of an automated gun turret, would be easier to affect rather than harder.
So what is Cha Dawn supposed to be? The GURPS book makes it clear that he does possess some extra-ordinary qualities beyond psychic abilities, in a timeframe that would make it impossible for him to be engineered on the planet. He can't have been engineered before planetfall either, since the humans didn't know the air was toxic (and thus wouldn't know that they'd need to make him capable of breathing the air). Hence, he's not just an elaborate hoax. However, the believe amongst the cult of the planet, that he was genetically engineered by Planet to facilitate communication, doesn't work either, since the planet wasn't fully sentient yet at that point.
In the Centauri: Arrival prequel story, Cha Dawn is the child of a Gaian talent after she slept with a solider during a night out on patrol. However, when Deirdre and Zakharov decided to find out who is this strange kid that has been leading troops against them, they couldn't find any genetic match to any citizens on record.
Planet doesn't need to be fully sentient to be able to produce a new variety of mindworm. If the Cult is right, Cha Dawn is essentially a human-shaped mindworm boil, or a human child repurposed into one, that was adopted and educated by the Cult of Planet. He's not part of the Planetmind for the same reason that Deirdre's worms aren't, and the only real difference is that the mind that he's developed is on the level of a human Talent and is running a faction.
So why doesn't Free Drones like Green Economies?
It directly opposes their pursuit of personal wealth and self-satisfaction. They're focused on improving their living standards above all else, the environment be damned.
Furthermore, environmentalism is largely an intellectual movement. Considering the Free Drones' disdain for even 'blue sky' scientific research with real life application, they will likely think of philosophers and ideologist that promote environmentalism very lowly.
Going off the above, are the Free Drones to an extent Hedonists?
Well, they are former Hivers trying to become Morganites. Depending on how you view the Morgans, the answer could be either yes or no.
Further depends on how you define Morganite. The Morganites and Drones generally don't get along because the Morganites are capitalists while the Drones are old-school communists. The Morganites want to get rich, while the Drones want everyone to be. That's why the thing that most gets their gander is not having a Eudaimonic future society: it means that, deep down, your desire is *not* to make your people happy.
What is Gaia's Landing◊ (and most Stepdaughter cities, for that matter) built out of/on? It looks like some weird tree to me, but that seems unlikely.
It kind of looks like a sci-fi anthill and termite mound.
How can humans win an Economic Victory over aliens, and vice versa? Aren't the Progenitor economies operating in self-sufficient autarky?
Probably because the Progenitors are not brought like the rest of Planet. Economic Victory is essentially generating enough power (both in energetic terms and literally, as in Chiron, due to the energy-based economy, they're the same thing, as Morgan says) to essentially buy all other factions' bases. Unless you have a odd game where the Progenitors have overrun most of Planet, then it stands to reason that its game-over for them as the economic victory winner essentially rules Planet and can simply have all human factions destroy the Progenitors. At least in Diplomatic Victory it actually makes more sense because you need to wipe out the Progenitors before winning diplo-victory.
Since the cost of the victory is calculated by determining how much it would cost to mind control every base perhaps you umm...mind control all their bases?