Dwarves are well known to everyone, expert at mining and crafting, stubborn as stone; those are the stereotypes outsiders have of them, although they aren't far from the truth.
Gnomes, on the other hand, are a bit different; they are naturally optimistic and enjoy carving gems, but there is also another important point: Gnomes were among the first races on this planet to start conducting scientific experiments and industrialization.
In theory, once a civilized race masters industrialization, they should advance by leaps and bounds. However, the reality of the Gnomes' strength is quite delicate. It is lower than that of the Dwarves but is still enough to protect themselves from being destroyed by other cities in the Dark Region. Yet, that is as far as they go. Logically, if Gnomes truly possessed powerful mechanical manufacturing abilities, sweeping across the entire Dark Region wouldn't pose a problem.
But they can't do it.