The only question is why is this only being done for FSX and not FS9
There's simply no way this could be ever done in FS9 for many reasons:
- FS9 doesn't support vertex-skinned animations, which are crucial to create realistic people. When FSX came out, many joked about the fact it included walking animals, but that technology, which FS9 doesn't support at all, is what makes humans animations possible as well.
- FS9 doesn't support the concept of Simobjects and Ground vehicles, which are special cases of airplanes that can be controlled using Simconnect, which is not available on FS9 either.
- The whole program logic is made using our Python script engine, that we made for FSX only, and it wouldn't be possible in FS9 either, since it also relies heavily on Simconnect.
So no, it's not a commercial choice, it's a technical choice and, in fact, there's no choice at all: this stuff simply can't done in FS9.