Sooo... if we're talking about lore, lets have some fun:
How would Andreas Cestelle handle the following situation:
He needs item X. Item X is extremely rare, only a handful of them have ever been found and they sit in the collections of extremely rich and powerful NPCs, Andreas doesn't even know exist. Andreas also doesn't know that these individuals would be willing to part with said items for the right price.
Even if Andreas gets the names of these individuals, they hardly have any interest in interacting with what they see as a "normal person" (not everyone on this planet will care about the WOL, especially not uber rich folks that live in their own little world).
So basically, Andreas is stuck.
Enter Rowena: she has a vast network, knows of these individuals and has contacts that have contacts in good standing. She offers to be the broker, for a modest ... or not so modest (poor Gerolt), fee.
How is that any less believable, from a lore PoV, than "eh just smack random mobs until you drop the item", especially if said mobs have nothing to do with the relic at all?
I mean Living memory is an artificial zone constructed from beings from another world. Why the hell would Demiatmas even drop there?