You're welcome.
My view is that the conflict is so scattered and wide ranging that Vasudan and Terran ships are scattered throughout, in nearly every system. They're either leftovers from previous offensive campaigns, stragglers, spec ops or even sappers. This is why they're in Ross 128, Betelgeuse and other systems. None of the systems are truely secure.
However, when it comes to the contested systems, you have massive fleet battles, entrenched troops, and all the things one would associate with full out combat. That's where the real war is/was, while the other stuff, even the stuff you start FS1 doing is really just a side show to the real fight.