The lack of security in old Gates made the existence of a central dimensional hub both impractical and dangerous.
To make matters worse, even if the Courts had the space and the resources to establish such a place for each one of their branches, it would also mean that once one of them was exposed the others would quickly follow.
The best compromise the undead had found during the centuries was to set up only a few Gates for each branch.
On the one hand, it meant that reaching most destinations required lots of time compared to the human network. On the other hand, the extra passages and the authorization protocols worked as security measures, compartmentalizing the various branches belonging to the same Court.
***
Distar Marquisate, City of Zaqua, a few seconds after the fall of Derios' branch of the Dawn Court.