However, I'd like to know why. These nodes are fundamentally no different from a regular node. How difficult would it be to add these items to the survey loot table from a development standpoint?
From ZOS's development philosophy, they seem to like making new materials rare. They did it CP 150/160 mats before hand. They did it again with jewelry upgrade mats. And while they do occasionally tweak stuff, I'm still getting 1 ruby ash from each non intricate staff I decon from drop loot. Maybe they think it keeps the game economy functional with artificial scarcity, I don't know.