Yep! Gameplay mechanism vs story.

So, using this thought process, Etheric Light should only be available in PoE and even then, only when fighting a Servitor a/k/a Skolas. Right? It sure seems like they bent over backwards to make it available. Or, they realized limiting it this dramatically would be absolutely ridiculous. So if they are willing to bend the rules this drastically than there is no reason my idea can't be implemented as well.

They clearly didn't think it throughout enough, the etheric light economic contradict to story and lore. They want players to farm, but then they realize the source of this material would be too scare, so they simple give up the story itself. But I don't think they will add another way to get etheric light.