Jiang Gu was chosen by Marquis Yunxiao long ago to work for him.
Back in the M45 Star Cluster, the civilizations supported by Marquis Yunxiao weren't just one. The reason you don't see them now is because the Maoshi Star Civilization quickly rose up, and other civilizations became discarded pawns of Marquis Yunxiao!
Now that the Maoshi Star Civilization can't compete with the Blue Star Civilization, there are no other civilizations in the entire M45 Star Cluster that can rival them except the Zerg.
Marquis Yunxiao naturally wouldn't want to invest more resources in helping them.
The Constant Star Furnace was destroyed, the core circle was breached, and the ten Mechanical Planets were gone. It's like losing the armory and energy reserve; how can this war be fought?
As long as the enemy controls this place, the main fleet outside is nothing more than rootless duckweed. Without support and supplies, they'll be wiped out sooner or later!