I believe that Lockheed Martin will eventually be able to license Prepar3D for 'entertainment use' at some stage. I know there is another company making a sim for all, planes, cars, boats and even dogs! It's called Outerra. I don't know whether if it will be compatible with the current add-ons we have for FSX and FS9 although I'm sure that the developers can make it compatible if the market is strong.
You can find more about Outerra here http://outerra.com/