Yeah, I mean I've got no problem with technological advances, but if this was done with von Neumanns then holy ****, the setting has changed, and if it wasn't well...
Let's do the math.
The moon's equator in the screenshot is banded by about 50 of the hexagonal domes. Since only half the equator is visible, we'll assume it takes 100 domes to completely belt the moon's equator.
The moon has a circumference of 10,921 km. Each dome is therefore 109.21 km across. This gives each hexagonal dome an approximate radius of 54.6 kilometers, and an internal area of 7,745 square kilometers.
Treating each dome (for ease of calculation) as a hemisphere, each dome has a surface area of 18,731 square kilometers. Assuming a thickness of ten centimeters and a flat Lunar surface (har har), each dome's actual material has a volume of 1.873 cubic kilometers. (These are arbitrary numbers, but quite optimistic, I think. In reality each dome is probably squashed rather than hemispherical, but I think it's a fair tradeoff for the thin domes, use of diamond and concessions to terrain regularity.
Assuming the domes are made of industrial diamond, they have a density of 3.52 grams per cubic centimeter.
Each dome contains 1.9 x 10 ^ 15 cubic centimeters, which at a density of 3.52 grams per cubic centimeter comes out to
a total mass PER DOME of 6 690 000 000 metric tons! (Unless I screwed up.)
By comparison, if we treat the mighty Colossus as a cylinder of of steel six kilometers long and one high, it has a volume of 4.7 cubic kilometers, with a mass of 36 895 000 000 metric tons. So the Colossus would mass about the same as six domes, assuming it were a solid block of steel (which has twice the density of diamond)...
...but assuming that the domes take up the entire Lunar surface with perfect efficiency, you need 4897 domes to cover the entire planet...
...and the total mass of all those domes is equal to about 888 Colossi.
Now you might be tempted to say that each dome is nowhere near as complex as the Colossus, which is why the Colossus took 20 years to build, but remember that each dome also contains all the necessary terraforming and general life support equipment, PLUS they have to be self-repairing to deal with constant impacts because the Moon is a huge target and has no atmosphere.
So the EA could probably do it, if they had von Neumanns (the total mass of the domes, while formidable, could easily be obtained just by disassembling Ceres), but the question then becomes why they struggled to build the Icanis. If you can build self-supporting domes of this size in a gravity well, you should be able to build a heck of a lot of destroyers or beam weapon platforms...and for that matter you could wall off the node with a massive shell of tremendous thickness (!).
Not to mention that if you can build an autonomous Neumann to assemble these domes you can build autonomous Neumanns that can build and then fly a combat fighter...meaning the EA should be defended by millions, maybe billions of drone weapons constructed by gray gooing the less valuable bits of the Solar System.
Also the whole blimp/F16 metaphor is faulty as heck. This is more like 'a society that can build F-16s versus a society that can build shells of F-16s by the trillions...and could clearly therefore build full F-16s by the billions'.