It can be. Generally since AI progress isn't really an issue for us, we take a set of EMP's in to paralyze it all, move both our fleets in and do what we can til the turrets come out of it. The only things still active typically are the core turrets, and maybe a few starships that are immune to EMP, which in our game at the moment is like 25 spires and 20 raids on each system. Our resource gain is so well done, (Due to us holding over half the map at this point) that rebuilding our fleet only take a few mins, and we have to many turrets in the system before if some slip through while we are rebuilding, it isn't a big deal. That and 2 super forts, and a 1 of each fort for both of us.