But I am talking about Animusphere's Astromancy Magecraft specifically. The reason it worked so well in LB5, as Holmes explained, was because of LB5's cosmology which is pretty much the Greece's model were super compatible with it. So while this magecraft doesn't need reality to match, if the condition of the world in reality is similar to what said magecraft is based on, it has extreme bonus. That's the point, it means that the AoG world has different layout of the cosmos and it was changed later, so these kind of magecraft lost huge power bonus due to "reality" is now different. And while it is texture based, I can see it (geocentric) being a default thing back then for all textures just with slight differences between the religions.
I don't see how their infighting caused all of them to be imprisoned. Are you saying they all cast Stupefy onto each other all at once while trying to one-up each other? And even if that is the case, who imprisoned them for being naughty? Was it the same as when the world itself sealed Tiamat? Because even in that case, they have to already be there causing problems first, then they got sealed.This is from the same chapter that established the Outer Gods are in a major conflict against each other, so that's what makes the most sense as the cause of their imprisonment.