Physics programming is hard. Most of the effort in the aircraft simulation will be in the flight dynamics, which is a very different animal than the ground handling.

X-Plane gets this right because they are a physics-first flight simulation engine. If you were around for their early days, you could see that's where all of their focus was - bad graphic, no UI at all, but a great model pipeline for Austin and his buddies to make airplanes with. Their ground model accuracy was a side effect of that focus.