There is a reason the Ult where once among the most feared civilizations in the M-0 Galaxy . Their technology and fighting skills were of such renowned magnitude, that neither the Shiss nor the Nul wanted to make the Ult angry.
Even the Xunx stayed away from Ult space.
Even after their sudden reversal of agressive expansion, the Ult remained a technological advances species.
The core reason was the Vaate Class Battleship. A mighty garantor of Ult supremacy.
The Vaate class of 700 OTT replaced the Plattk class and was upgraded and modernized constantly.
The Ult have a tendency to hold on to a design if it is successful and make little changes until something new proves to be really superior. Ult design is among the most reliable.
Vaate Class made a serious contribution in defending the Union from the last Y'All invasion as there were still many available.
Vaate Surplus ships hastily reactivated after Stahl returned, were among the first ships with Translocator cannons and the new Para Diim shields ( 1st Generation)
Most Vaate have been scrapped, a few have been demilitarized and sold on the civilian market. About 500 remain in various Bone Yards and five are displayed in Museums.
 Of course no one, including the Ult want to make the Terrans angry (pre Union)