I don't really buy the whole deal of neglect of strike crafts within the GTVA. If anything FS2 proves the opposite here. Take the Erinyes, Perseus, or Pegasus as an example. The only real advantage I can see the UE has is that it can deploy all of it's forces to one theater while the GTVA might only be able to deploy a couple of fleets as they have vastly more territory to cover. So maybe I could be able to fight a defensive war, but going on the offensive? Hardly.
Given your response I assume that UE does not have access to any other star system, right?
The GTVA LEARNED from Capella, and the events of FS2. The Erinyes is great for blasting fighters into fifty million pieces a few seconds faster than a Kulas armed with a Balor can, but really, capital ships such as the Ravana, Demon and the Juggernaught, the Sath, is what really gave the Shivans a leg up. Remember, the Erinyes, Perseus and what-not are still used in BP, Al'Faddil (how however you spell it) flies an Erinyes.
So from what Darius says, the GTVA have turned their doctrine from surgical strike actions, with capital ships being used as fire-support, as seen in the retail campaign, to a capital-ship based doctrine, in which the fighters provide cover, and forward reconnaissance for capital ships entering the field of engagement. Forced Entry for example, they were clearing the way for the fleet.
We don't need another Erinyes clone to do that. We need something that can be deployed fast, moves fast, shoots fast, and packs light, like the Kulas. The Erinyes is still there, but remember, the GTVA lost pretty much 1/2-3/4 of its fighter squadrons in the Terran 3rd Fleet. To replace these, they needed something cheap as well, which fits with their doctrine of light spacecraft.
And he didn't say strike fighter squadrons had been neglected, these squadrons clearly still exist, but to bolster the ranks, and to boost the "Cannon-Fodder" the GTVA had available to them, what's better than the Kulas and the Myrmidon? They're cheap, do their jobs, and I would assume they have a relatively high attrition rate compared to the strike fighter squadrons, which I also assume would be something similar to pilots flying the F-22 Raptor at the moment. They're the Strike Squadrons of the GTVA, but now the GTVA's buying lots of F-16s and F-15s to bolster the ranks, and support the operations of the F-22 Raptors, which'll soon be supplemented by the F-35 JSF, which is like the Artemis in some sense. You could almost say, Perseus fighters were designed to protect the bombers of their generation, such as the Artemis. Akin to how some strategists could say the F-22 is at it's base level, there to support and escort F-35s on their deep strike/infiltarion missions. Then you have the F-15s and F-16s, the Myrmidons and Kulas fighters, they're there to carry out your line jobs.