The most essential parts included aircraft manufacturing, automobile and tank manufacturing, etc... Most of these factories were destroyed by bombing, and a few were relocated, leaving behind only a wasteland.
In this situation, the dwarves can hardly maintain any industrial operations. The little they have left can only barely continue with raw materials and electricity provided by allies from the south.
Not joking at all, the dwarves are struggling to manufacture bullets on their own, and ammunition like shells can only be supplied by the elves. Many weapons for the troops near Furnace Fortress are reduced by one when broken.
Without the support of modern industry, firearms become non-renewable resources, and now the dwarven commanders finally deeply understand the meaning of this statement.
