Yeah, there is no actual economy in this game. GP and gear is a resource to be managed by players and provides an alternate advancement track that exists alongside xp and level progression.
However, accepting the unrealistic premise and trying to explain it amuses me, personally. I prefer when the reality of the game world is taken at face value. Yes, raise dead always costs 5000 gp of diamond and merchants stock 5000 gp diamonds on a regular basis. Yes, experienced adventurers can survive falls from exceedingly high distances. Yes, every arcanist, bloodrager, magus, occultist, sorcerer, and wizard is actually a geometry expert and always places the center of the fireball exactly where they want it.
But I'm strange.
Fabricate sure is a spell, innit?