Something crossed my mind today. The FSX engine models the entire world, more or less, so why, instead of creating your own engine, not just license theirs. Then you just have to create the aircraft, enemies, and a mission builder/campaign(I say just simply because licensing the engine would save all that dev time creating your own).

I knwo what your thinking: but FSX looks kinda bad that low. In that case, you simply cut out most of the world and bump up the detail to a specific region, like the scenery packs do. I'm sure I'm over simplifying this, but the recently release F18 addon for FSX made me wonder why no one has done this(out side the combat flight sim series way back when).

Because it's expensive? Some large companies do use a modified FSX engine (ESP) for simulators.

The items you list, aircraft, enemies, mission builder, campaign are just as big (if not larger) in scope. It's quite doable but to package the FSX engine with a consumer product would be expensive and not worthwhile unless MS decided to 'gift' it to the community when FLIGHT is released.

Probably we'll have something with the VRS TacPac and its future development with SDK to make models and weapons and so on in FSX.
FSX@War is a mod to implement AI and mission generator...

I hope they'll find the way to simulate FLIR... and we'll have a Real "All Inclusive" Flight Simulator.

Good points guys. You answered my question.

short answer, it's a bad engine. poorly optimized.