I agree with your "easy money" theory for the most part, but it falls flat on FC4. Sure, it might be easy enough to dumb down an already-existing module and then sell it again, but I don't think FC4 will be as "easy money" as they think it would be since these aircraft already exist as DCS-level. Remember, the main reason FC3 is such a hit is because you cannot get those aircraft anywhere else; this clearly won't be the case for FC4 so while they might be able to push it out the door sooner, I doubt it will bring them good money.
As for the choice of modules, I think you're giving them more credit than they deserve. Didn't they just stumble onto WWII due to a bad deal? Not really sure how that transpired as I wasn't paying attention at that time and have little interest in old warbirds. Then again, aren't most of the older aircraft/helos 3rd-party projects anyway?
If you wish to give ED any sort of credit for any sort of percieved brilliance, simply look at how their DCS 2.5 release is going -- Wags having to "promise" a release date, the software being pushed out the door in an unpolished state just to meet the "promise", an estimated 1-2 week turnaround time between beta and release that turned out to be a couple of months, and so on and so forth.... brilliant? Probably so if you take each part on it's own. Beautiful eye candy. Good FM on modules. Not having to fiddle with MS-DOS windows to update your software. But the whole? Broken stuff are still broken. An unexpected increase in RAM requirements. Microstutters still existing on certain hardware configurations.