The way LM is handling the development priorities of P3D is actually business savvy for them. They are, first and foremost, a military scenario training company. Easy for me to speculate that they contract a training product with a client (government, agency, etc.) then outsource any scenery, navaids, etc. FOR THAT SPECIFIC TRAINING PRODUCT to the existing development community (Orbx, Milviz, etc.).
By leveraging the existing development community, LM can focus its internal resources on the base sim engine. As you might have noticed from the AMA, internally they are more focused on performance and VR than scenery, vehicles, etc.
Full disclosure and my opinion only: I have no inside track to LM. I do have 20+ years in private sector contracting with US government agencies for technology related products. LM does not need the sim users except for a testing base. LM most certainly need the developers who also work with the sim users.