Except you can't sell to devout, because they're the ones who outcast you in the first place. I know right? The floran went from being an interesting take on the cliché plant people, to bland and uninteresting with just one update!
That's why pirates like Thornwing exist, nefarious for smuggling and such. Heck, Grounded regularly raid Flightless tombs and temples as a sign of protest, it's not hard to believe that vulnerable supply convoys and fueling stations might get hit. That said, it's hard to say the crystals are mined. It's entirely possible that they are manufactured artificially, or that they're seeded and harvested like crystal plants. Of course, you can't say for sure that they are manufactured either. Ultimately it's vague. If they did appear outside of Avian space, then you'd expect the other races to have made more use of them. But they haven't.
I've not heard of Grounded raiding Flightless tombs and temples, if possible, could you provide a link to the source? As for the crystals being manufactured, I do feel like it's unlikely, if they were created artificially using common materials, or even uncommon materials, I feel as though the other races would have begun manufacturing them as well. Then again, you're right, if they were just being mined in the fast place, other races would likely have stumbled upon them eventually. I suppose, whether or not they're mined or manufactured, whatever it is they're made of is most likely much more common in the space surrounding Avos.
I think the thing about temple raiding comes from the one interactive log relating to the Agarans and the one ship. I'll see if I can find a link.
http://playstarbound.com/wp-content/uploads/2014/05/sparrow3.html Though there is a lot of information in this that is contradictory and canon(Really hard to say what is and isn't canon according to the chucklefish), nothing more than what exists in most the other canonified lore. This here isn't quite accurate. Just because one race knows something doesn't mean they all do. For one, it could be a complex or non-straight forward method. It could require elements that simply appeared in greater concentration on Avos, and thus allowed the discovery sooner. It could also be that Avians discovered the technology early and the other races simply followed a different path, eliminating the need to evolve two trees of technology.
When i asked Demanrisu about the agaran, whether they were genetically modified apex, he said NOT NECESSARILY and linked that. So i'm guessing agaran are 1. Genetically modified Apex with Floran dna (1st generation) ; 2. sporified-other races that transform into Agaran as well; dead-space style. Oh and that the sparrow and abridged avian lore are "probably" canon...
When it comes to the origins of avian crystals, I think the most accurate answer is the one people have the hardest time accepting. Nobody knows. Seriously. just leave it at that.
I guess we'll have to wait until some more information is released, if Chucklefish is actually willing to get involved with the specifics on how these crystals work.
Yeah I imagine all the avian crystals are produced or mined in some top secret temple or factory on Avos, and are then distributed to the general avian population, though with heavy regulation. Sometimes avians become grounded and bring all the crystal tech they already had with them. They are probably stolen too. Wouldn't be surprised if the avian pirates steal from Avos a lot.
Not exactly the same thing. They could smuggle crystal tech items off of Avos and stuff like that. Doesn't need to be a direct all out assault.
Arguably things are smuggled in and out of the U.S. all the time. The difference here is you'd have an even harder time controlling things since you can't possibly cover every approach to a planet without nearly infinite resources. (A note for those of you wielding fleets back in the day). There's just too much space.