Reply...
Casey,
This answer is complex, but I believe that the root of it lies with us, in a sense. Third-party development for combat flight sims has allowed CFS2 and CFS3 to expand well beyond their initial intended audiences. CFS2 has been expanded into virtually every CFS2 theatre, not to mention Korea, WWI, and Vietnam, and CFS3 has done the same.
Accordingly, we have become in a perverse sense victims of our own success. Sims like IL-2, though not impossible, are much tougher to keep alive because much of the development is software-based, and developing third-party add-ons becomes that much tougher. Additionally, CFS2 and CFS3 do not require a high-end computer to run, increasing their respective audiences.
Lastly, the Mission Builder feature of CFS2 allows those who get familiar with to have virtually endless ways to keep adding to the sim; all you need is a vision and a modicum of skill. This is in addition to the other add-ons, including aircraft, guns, and the shining examples of Malta, Gibraltar, Pantelleria, and many of MaskRider's Pacific airfields, to name a few.
CFS2 and CFS3 provide their users with many ways to keep the game alive and kicking. I do think that CFS1 may have been a bit too primitive to be sustainable long term, CFS2 really picked up where CFS1 left off and ran with it.
Did you really think that Microsoft ever envisioned that we'd come this far, nearly eleven years after the fact? I don't, and I love it!