For follow up on the "just fly around", its my understanding that the trading guild functions (like shop restock, guild ships flying around, etc) go on whenever there is a shop there. To keep the game from basically crashing or being super slow due to trying to keep track of thousands and thousands of shops, shops only spawn in (are created) when a player actually goes out to find them.
Means there are no shops at all in unexplored space, and its only when you're sitting around in an area for a little bit that the game goes "Welp, okay, player is here, time to see if we want to randomly spawn a shop in this sector or not".