I mentioned in the past that this would be the Xenon's strong point before the Cradle of Humanity dlc.
They pretty much only have energy cells and raw minerals and they can assemble anything from that.
Where as the Commonwealth have dozens of wares that require resources that require raw resources under that before they have a ship.
Terrans have powerful weapons and better Logistical Support on top of that, easy to bet on who will will this war, plus allot of their weapons are designed for killing Xenon.
The Xenon are on their last legs.